Skip to content
https://bmj.com

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
4
PASS
5
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
86
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
92
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
91
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

730 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.18 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

229 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.107

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

979 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

3.07 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
15
5 PASS 4 REVIEW 4 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (1.9 MiB of 1.9 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Bundles
Action
28 scripts, 538 KB unused
FIX
28 scripts, 538 KB unused
Warning::
https://securepubads.g.doubleclick.net/pagead/mana...: 132 KB unused (70%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://analytics.bmj.com/gtag/js?id=G-LHT0ZJKRSY&...: 78 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://analytics.bmj.com/gtag/js?id=G-N0KVPL2464&...: 72 KB unused (40%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL: 67 KB unused (33%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/destination?...: 65 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 538 KB
538 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js188 KB132 KB (70%)✓3rd
https://analytics.bmj.com/gtag/js?id=G-LHT0ZJKRSY&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421195 KB78 KB (40%)✓3rd
https://analytics.bmj.com/gtag/js?id=G-N0KVPL2464&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421180 KB72 KB (40%)✓3rd
https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL200 KB67 KB (33%)✓3rd
https://www.googletagmanager.com/gtag/destination?id=DC-13070819&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421130 KB65 KB (50%)✓3rd
https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otBannerSdk.js131 KB63 KB (48%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-8P7810XE1M&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421152 KB61 KB (40%)✓3rd
https://www.bmj.com/_next/static/chunks/pages/_app-58067fd7f289b1e2.js53 KB—✓3rd
https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.js46 KB—✓3rd
https://www.bmj.com/_next/static/chunks/363-c279d1e5e0049870.js5 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

F
Page Weight Inventory
Action
76 resources · 1.9 MB · 538 KB savings available
FIX
76 resources · 1.9 MB · 538 KB savings available
Warning::
Page weight 879 KB over 1MB target
Got: 1.9 MB Expected: ≤ 1 MB
Info::
~538 KB of savings available
Warning::
75 third-party resources (100% of weight)
Info::
1 resources over 200KB
76 resources · 1.9 MiB · 75 third-party 878.8 KiB over 1MB target
JavaScript 81% · 1.5 MiB
Image 12% · 219.4 KiB
Font 3% · 47.9 KiB
Other 2% · 44.5 KiB
CSS 2% · 29.1 KiB
Document 1% · 26.6 KiB

~537.6 KiB of savings available

Remove unused JavaScript: 537.6 KiB
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Page Weight Budget
Action
1.9 MB transferred, 76 requests
REVIEW
1.9 MB transferred, 76 requests
Info::
Page weighs 5.9 MB (1.9 MB transferred)
Warning::
JavaScript is 1.4 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.4 MB
Info::
76 HTTP requests
Info::
Estimated 0.39 g CO2 per page load
1.9 MB / 2.4 MB budget
1.9 MB transferred
76 requests
0.39 g CO2 per page load
JavaScript 1.4 MiB 74%
Images 218.2 KiB 11%
Other 146.7 KiB 8%
Fonts 47.9 KiB 3%
Other 26.6 KiB 1%
HTML 25.2 KiB 1%
CSS 24.1 KiB 1%
Other 3.1 KiB 0%
Other 331 B 0%
0 2.4 MB 4.9 MB
Approaching limit

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

B
Image Optimization
21 images, 0 KB saveable
REVIEW
21 images, 0 KB saveable
Info::
All images are well-optimized
21 images 218 KB
0 oversized -0 KB
8 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1334ms total JS execution
REVIEW
1334ms total JS execution
Info::
https://www.bmj.com/: 222ms CPU time
Info::
Unattributable: 199ms CPU time
Info::
https://cookie-cdn.cookiepro.com/scripttemplates/2...: 157ms CPU time
Info::
https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL: 153ms CPU time
Info::
https://cookie-cdn.cookiepro.com/scripttemplates/2...: 108ms CPU time
Warning::
Third-party scripts: 1334ms (100% of total)

Main Thread Breakdown

Script Evaluation 59% Other 15% Style & Layout 10% Script Parsing & Compilation 9% Rendering 3%
ScriptTotalScriptingParse/CompileParty
https://www.bmj.com/222ms9ms1ms3rd
Unattributable199ms7ms0ms3rd
https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otTCF.js157ms139ms2ms3rd
https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL153ms124ms26ms3rd
https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otBannerSdk.js108ms66ms14ms3rd
https://analytics.bmj.com/gtag/js?id=G-N0KVPL2464&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_2026042197ms81ms12ms3rd
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js97ms73ms21ms3rd
https://www.googletagmanager.com/gtag/js?id=G-8P7810XE1M&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_2026042195ms83ms11ms3rd
https://analytics.bmj.com/gtag/js?id=G-LHT0ZJKRSY&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_2026042182ms69ms13ms3rd
https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.js73ms63ms9ms3rd

Showing top 10 of 11 scripts

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
2 fonts (48 KB)
PASS
2 fonts (48 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

48 KB total

Render-blocking

0

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s FCP 730 ms LCP 1.2 shttps://www.bmj.com/_next/static/media/if_std_rg-webfont.90c6a082.woffif_std_rg-webfont.90c6a... https://www.bmj.com/_next/static/media/if_std_rg-webfont.90c6a082.woff — 23.6 KiB — 30 ms — font-display: swaphttps://www.bmj.com/_next/static/media/if_std_bd-webfont.ed1e08b9.woffif_std_bd-webfont.ed1e0... https://www.bmj.com/_next/static/media/if_std_bd-webfont.ed1e08b9.woff — 24.3 KiB — 31 ms — font-display: swap
if_std_rg-webfont.90c6a... woff swap
Size 24 KB
Load time 30 ms
Start 255 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
if_std_bd-webfont.ed1e0... woff swap
Size 24 KB
Load time 31 ms
Start 256 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~14 KB and ~28 ms

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
Network Waterfall
76 requests over 1770ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 730 ms LCP 1.2 shttps://bmj.com// https://bmj.com/ — 301 — 261 B — 21 ms — h2https://www.bmj.com/www.bmj.com/ https://www.bmj.com/ — 200 — 23.3 KiB — 55 ms — h2https://www.bmj.com/cdn-cgi/speculationwww.bmj.com/cdn-cgi/speculation https://www.bmj.com/cdn-cgi/speculation — 200 — 232 B — 12 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fthebmj-frontend.bmj.com%2Fnext-resources%2Fthebmj-logo-large.png&w=110&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fthebmj-frontend.bmj.com%2Fnext-resources%2Fthebmj-logo-large.png&w=110&q=75 — 200 — 1.4 KiB — 100 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/otSDKStub.jscookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/otSDKStub.js — 200 — 9.3 KiB — 60 ms — h2https://thebmj-frontend.bmj.com/next-resources/oneTrust.jsthebmj-frontend.bmj.com/next-resour... https://thebmj-frontend.bmj.com/next-resources/oneTrust.js — 200 — 655 B — 96 ms — h2https://securepubads.g.doubleclick.net/tag/js/gpt.jssecurepubads.g.doubleclick.net/tag/... https://securepubads.g.doubleclick.net/tag/js/gpt.js — 200 — 33.6 KiB — 116 ms — h3https://www.bmj.com/_next/static/css/187b6a924df2e0f7.csswww.bmj.com/_next/static/css/187b6a... https://www.bmj.com/_next/static/css/187b6a924df2e0f7.css — 200 — 24.1 KiB — 26 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fcomprehensive_school_students_2HTJ336-copy.jpg&w=600&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fcomprehensive_school_students_2HTJ336-copy.jpg&w=600&q=75 — 200 — 24.2 KiB — 196 ms — h2https://cdn.pbgrd.com/core-bmj.js?t=1653636702cdn.pbgrd.com/core-bmj.js?t=1653636... https://cdn.pbgrd.com/core-bmj.js?t=1653636702 — 200 — 4.0 KiB — 105 ms — http/1.1https://www.bmj.com/_next/static/chunks/webpack-6ef43a8d4a395f49.jswww.bmj.com/_next/static/chunks/web... https://www.bmj.com/_next/static/chunks/webpack-6ef43a8d4a395f49.js — 200 — 1.5 KiB — 78 ms — h3https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.jswww.bmj.com/_next/static/chunks/fra... https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.js — 200 — 46.1 KiB — 99 ms — h3https://www.bmj.com/_next/static/chunks/main-fc788ce92ccfeb2d.jswww.bmj.com/_next/static/chunks/mai... https://www.bmj.com/_next/static/chunks/main-fc788ce92ccfeb2d.js — 200 — 32.3 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/pages/_app-58067fd7f289b1e2.jswww.bmj.com/_next/static/chunks/pag... https://www.bmj.com/_next/static/chunks/pages/_app-58067fd7f289b1e2.js — 200 — 53.3 KiB — 104 ms — h3https://www.bmj.com/_next/static/chunks/100-933a18c4a3ce9023.jswww.bmj.com/_next/static/chunks/100... https://www.bmj.com/_next/static/chunks/100-933a18c4a3ce9023.js — 200 — 2.9 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/363-c279d1e5e0049870.jswww.bmj.com/_next/static/chunks/363... https://www.bmj.com/_next/static/chunks/363-c279d1e5e0049870.js — 200 — 5.1 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/pages/index-c3741423fcbb2feb.jswww.bmj.com/_next/static/chunks/pag... https://www.bmj.com/_next/static/chunks/pages/index-c3741423fcbb2feb.js — 200 — 6.4 KiB — 95 ms — h3https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_buildManifest.jswww.bmj.com/_next/static/Z44gBmeiSp... https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_buildManifest.js — 200 — 834 B — 95 ms — h3https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_ssgManifest.jswww.bmj.com/_next/static/Z44gBmeiSp... https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_ssgManifest.js — 200 — 552 B — 95 ms — h3https://api.altmetric.com/v1/donut/116132730_60.pngapi.altmetric.com/v1/donut/11613273... https://api.altmetric.com/v1/donut/116132730_60.png — 302 — 614 B — 134 ms — h2https://api.altmetric.com/v1/donut/160173974_60.pngapi.altmetric.com/v1/donut/16017397... https://api.altmetric.com/v1/donut/160173974_60.png — 302 — 245 B — 134 ms — h2https://api.altmetric.com/v1/donut/124733966_60.pngapi.altmetric.com/v1/donut/12473396... https://api.altmetric.com/v1/donut/124733966_60.png — 302 — 238 B — 134 ms — h2https://api.altmetric.com/v1/donut/101645304_60.pngapi.altmetric.com/v1/donut/10164530... https://api.altmetric.com/v1/donut/101645304_60.png — 302 — 241 B — 134 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 101 ms — h2https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLLanalytics.bmj.com/gtm.js?id=GTM-NF7... https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL — 200 — 200.4 KiB — 335 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fbrazil_person_computer_iStock-1246061014-copy.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fbrazil_person_computer_iStock-1246061014-copy.jpg&w=300&q=75 — 200 — 9.3 KiB — 13 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fadditional_therapeutic_strategies_for_alzheimers_disease.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fadditional_therapeutic_strategies_for_alzheimers_disease.jpg&w=300&q=75 — 200 — 8.1 KiB — 25 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fwillett_colleague_initiative.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fwillett_colleague_initiative.jpg&w=300&q=75 — 200 — 10.7 KiB — 18 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fteenager_getting_a_vaccine.png&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fteenager_getting_a_vaccine.png&w=300&q=75 — 200 — 7.4 KiB — 20 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F01%2Fcovid_vaccine_uk_2K28P8R.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F01%2Fcovid_vaccine_uk_2K28P8R.jpg&w=300&q=75 — 200 — 9.5 KiB — 154 ms — h2
0 ms 500 ms 1.0 s 1.5 s FCP 730 ms LCP 1.2 shttps://bmj.com// https://bmj.com/ — 301 — 261 B — 21 ms — h2https://www.bmj.com/www.bmj.com/ https://www.bmj.com/ — 200 — 23.3 KiB — 55 ms — h2https://www.bmj.com/cdn-cgi/speculationwww.bmj.com/cdn-cgi/speculation https://www.bmj.com/cdn-cgi/speculation — 200 — 232 B — 12 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fthebmj-frontend.bmj.com%2Fnext-resources%2Fthebmj-logo-large.png&w=110&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fthebmj-frontend.bmj.com%2Fnext-resources%2Fthebmj-logo-large.png&w=110&q=75 — 200 — 1.4 KiB — 100 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/otSDKStub.jscookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/otSDKStub.js — 200 — 9.3 KiB — 60 ms — h2https://thebmj-frontend.bmj.com/next-resources/oneTrust.jsthebmj-frontend.bmj.com/next-resour... https://thebmj-frontend.bmj.com/next-resources/oneTrust.js — 200 — 655 B — 96 ms — h2https://securepubads.g.doubleclick.net/tag/js/gpt.jssecurepubads.g.doubleclick.net/tag/... https://securepubads.g.doubleclick.net/tag/js/gpt.js — 200 — 33.6 KiB — 116 ms — h3https://www.bmj.com/_next/static/css/187b6a924df2e0f7.csswww.bmj.com/_next/static/css/187b6a... https://www.bmj.com/_next/static/css/187b6a924df2e0f7.css — 200 — 24.1 KiB — 26 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fcomprehensive_school_students_2HTJ336-copy.jpg&w=600&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fcomprehensive_school_students_2HTJ336-copy.jpg&w=600&q=75 — 200 — 24.2 KiB — 196 ms — h2https://cdn.pbgrd.com/core-bmj.js?t=1653636702cdn.pbgrd.com/core-bmj.js?t=1653636... https://cdn.pbgrd.com/core-bmj.js?t=1653636702 — 200 — 4.0 KiB — 105 ms — http/1.1https://www.bmj.com/_next/static/chunks/webpack-6ef43a8d4a395f49.jswww.bmj.com/_next/static/chunks/web... https://www.bmj.com/_next/static/chunks/webpack-6ef43a8d4a395f49.js — 200 — 1.5 KiB — 78 ms — h3https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.jswww.bmj.com/_next/static/chunks/fra... https://www.bmj.com/_next/static/chunks/framework-3b5a00d5d7e8d93b.js — 200 — 46.1 KiB — 99 ms — h3https://www.bmj.com/_next/static/chunks/main-fc788ce92ccfeb2d.jswww.bmj.com/_next/static/chunks/mai... https://www.bmj.com/_next/static/chunks/main-fc788ce92ccfeb2d.js — 200 — 32.3 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/pages/_app-58067fd7f289b1e2.jswww.bmj.com/_next/static/chunks/pag... https://www.bmj.com/_next/static/chunks/pages/_app-58067fd7f289b1e2.js — 200 — 53.3 KiB — 104 ms — h3https://www.bmj.com/_next/static/chunks/100-933a18c4a3ce9023.jswww.bmj.com/_next/static/chunks/100... https://www.bmj.com/_next/static/chunks/100-933a18c4a3ce9023.js — 200 — 2.9 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/363-c279d1e5e0049870.jswww.bmj.com/_next/static/chunks/363... https://www.bmj.com/_next/static/chunks/363-c279d1e5e0049870.js — 200 — 5.1 KiB — 95 ms — h3https://www.bmj.com/_next/static/chunks/pages/index-c3741423fcbb2feb.jswww.bmj.com/_next/static/chunks/pag... https://www.bmj.com/_next/static/chunks/pages/index-c3741423fcbb2feb.js — 200 — 6.4 KiB — 95 ms — h3https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_buildManifest.jswww.bmj.com/_next/static/Z44gBmeiSp... https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_buildManifest.js — 200 — 834 B — 95 ms — h3https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_ssgManifest.jswww.bmj.com/_next/static/Z44gBmeiSp... https://www.bmj.com/_next/static/Z44gBmeiSp9a1xlbTWw4j/_ssgManifest.js — 200 — 552 B — 95 ms — h3https://api.altmetric.com/v1/donut/116132730_60.pngapi.altmetric.com/v1/donut/11613273... https://api.altmetric.com/v1/donut/116132730_60.png — 302 — 614 B — 134 ms — h2https://api.altmetric.com/v1/donut/160173974_60.pngapi.altmetric.com/v1/donut/16017397... https://api.altmetric.com/v1/donut/160173974_60.png — 302 — 245 B — 134 ms — h2https://api.altmetric.com/v1/donut/124733966_60.pngapi.altmetric.com/v1/donut/12473396... https://api.altmetric.com/v1/donut/124733966_60.png — 302 — 238 B — 134 ms — h2https://api.altmetric.com/v1/donut/101645304_60.pngapi.altmetric.com/v1/donut/10164530... https://api.altmetric.com/v1/donut/101645304_60.png — 302 — 241 B — 134 ms — h2https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516static.cloudflareinsights.com/beaco... https://static.cloudflareinsights.com/beacon.min.js/v8c78df7c7c0f484497ecbca7046644da1771523124516 — 200 — 10.7 KiB — 101 ms — h2https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLLanalytics.bmj.com/gtm.js?id=GTM-NF7... https://analytics.bmj.com/gtm.js?id=GTM-NF7HCLL — 200 — 200.4 KiB — 335 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fbrazil_person_computer_iStock-1246061014-copy.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fbrazil_person_computer_iStock-1246061014-copy.jpg&w=300&q=75 — 200 — 9.3 KiB — 13 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fadditional_therapeutic_strategies_for_alzheimers_disease.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fadditional_therapeutic_strategies_for_alzheimers_disease.jpg&w=300&q=75 — 200 — 8.1 KiB — 25 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fwillett_colleague_initiative.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fwillett_colleague_initiative.jpg&w=300&q=75 — 200 — 10.7 KiB — 18 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fteenager_getting_a_vaccine.png&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2Fteenager_getting_a_vaccine.png&w=300&q=75 — 200 — 7.4 KiB — 20 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F01%2Fcovid_vaccine_uk_2K28P8R.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F01%2Fcovid_vaccine_uk_2K28P8R.jpg&w=300&q=75 — 200 — 9.5 KiB — 154 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2023%2F01%2Fclinical_research.jpg&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2023%2F01%2Fclinical_research.jpg&w=300&q=75 — 200 — 10.5 KiB — 25 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FCardiac-Syncope-540px.png&w=300&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FCardiac-Syncope-540px.png&w=300&q=75 — 200 — 5.3 KiB — 26 ms — h2https://www.bmj.com/_next/static/media/if_std_rg-webfont.90c6a082.woffwww.bmj.com/_next/static/media/if_s... https://www.bmj.com/_next/static/media/if_std_rg-webfont.90c6a082.woff — 200 — 23.6 KiB — 30 ms — h3https://www.bmj.com/_next/static/media/if_std_bd-webfont.ed1e08b9.woffwww.bmj.com/_next/static/media/if_s... https://www.bmj.com/_next/static/media/if_std_bd-webfont.ed1e08b9.woff — 200 — 24.3 KiB — 31 ms — h3https://badges.altmetric.com/?size=60&score=41405&types=mbvrtwfobadges.altmetric.com/?size=60&score... https://badges.altmetric.com/?size=60&score=41405&types=mbvrtwfo — 200 — 16.9 KiB — 48 ms — h2https://badges.altmetric.com/?size=60&score=6280&types=mbvrtfuobadges.altmetric.com/?size=60&score... https://badges.altmetric.com/?size=60&score=6280&types=mbvrtfuo — 200 — 16.9 KiB — 45 ms — h2https://badges.altmetric.com/?size=60&score=4008&types=mbvrtwfdbadges.altmetric.com/?size=60&score... https://badges.altmetric.com/?size=60&score=4008&types=mbvrtwfd — 200 — 17.0 KiB — 50 ms — h2https://badges.altmetric.com/?size=60&score=5040&types=mbvrtwfubadges.altmetric.com/?size=60&score... https://badges.altmetric.com/?size=60&score=5040&types=mbvrtwfu — 200 — 16.9 KiB — 42 ms — h2https://cookie-cdn.cookiepro.com/consent/565e50dd-f6e9-46d6-91cd-5c40a270264f/565e50dd-f6e9-46d6-91cd-5c40a270264f.jsoncookie-cdn.cookiepro.com/consent/56... https://cookie-cdn.cookiepro.com/consent/565e50dd-f6e9-46d6-91cd-5c40a270264f/565e50dd-f6e9-46d6-91cd-5c40a270264f.json — 200 — 2.6 KiB — 51 ms — h2https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.jssecurepubads.g.doubleclick.net/page... https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js — 200 — 187.7 KiB — 23 ms — h3https://secure.polldaddy.com/w/64555.jssecure.polldaddy.com/w/64555.js https://secure.polldaddy.com/w/64555.js — 200 — 5.3 KiB — 45 ms — h2https://geolocation.onetrust.com/cookieconsentpub/v1/geo/locationgeolocation.onetrust.com/cookiecons... https://geolocation.onetrust.com/cookieconsentpub/v1/geo/location — 200 — 286 B — 53 ms — h2https://vitals.vercel-insights.com/v1/vitalsvitals.vercel-insights.com/v1/vital... https://vitals.vercel-insights.com/v1/vitals — 200 — 166 B — 114 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FGaza_mourners_april_2026_3E8M8CC-copy.jpg&w=200&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FGaza_mourners_april_2026_3E8M8CC-copy.jpg&w=200&q=75 — 200 — 6.5 KiB — 22 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FIndia_ship_strait_hormuz_3E5CG7G-copy.jpg&w=200&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F04%2FIndia_ship_strait_hormuz_3E5CG7G-copy.jpg&w=200&q=75 — 200 — 1.7 KiB — 20 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F03%2Ftired-woman.png&w=200&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F03%2Ftired-woman.png&w=200&q=75 — 200 — 4.3 KiB — 15 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F03%2Foesophagus.png&w=200&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fbmj-chicken.bmj.com%2Fthebmj%2Fwp-content%2Fuploads%2Fsites%2F4%2F2026%2F03%2Foesophagus.png&w=200&q=75 — 200 — 1019 B — 17 ms — h2https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fwww.bmj.com%2Fsites%2Fdefault%2Ffiles%2Fstyles%2Fcover_360_480%2Fpublic%2Fhighwire%2Fbmj%2F393%2F8486.cover-source.jpg&w=200&q=75thebmj-frontend.bmj.com/_next/image... https://thebmj-frontend.bmj.com/_next/image?url=https%3A%2F%2Fwww.bmj.com%2Fsites%2Fdefault%2Ffiles%2Fstyles%2Fcover_360_480%2Fpublic%2Fhighwire%2Fbmj%2F393%2F8486.cover-source.jpg&w=200&q=75 — 200 — 36.0 KiB — 31 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otBannerSdk.jscookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otBannerSdk.js — 200 — 131.2 KiB — 38 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-NF7HCLL&gtg_health=1www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-NF7HCLL&gtg_health=1 — 200 — 392 B — 59 ms — h2https://cookie-cdn.cookiepro.com/consent/565e50dd-f6e9-46d6-91cd-5c40a270264f/019db08f-2242-7e99-8fee-18a7a8acb599/en.jsoncookie-cdn.cookiepro.com/consent/56... https://cookie-cdn.cookiepro.com/consent/565e50dd-f6e9-46d6-91cd-5c40a270264f/019db08f-2242-7e99-8fee-18a7a8acb599/en.json — 200 — 34.8 KiB — 41 ms — h2https://cookie-cdn.cookiepro.com/vendorlist/iab2V2Data.jsoncookie-cdn.cookiepro.com/vendorlist... https://cookie-cdn.cookiepro.com/vendorlist/iab2V2Data.json — 200 — 87.0 KiB — 35 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otTCF.jscookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/otTCF.js — 200 — 18.0 KiB — 25 ms — h2https://securepubads.g.doubleclick.net/pagead/managed/dict/m202604210101/gptsecurepubads.g.doubleclick.net/page... https://securepubads.g.doubleclick.net/pagead/managed/dict/m202604210101/gpt — 200 — 23.0 KiB — 30 ms — h3https://analytics.bmj.com/gtag/js?id=G-LHT0ZJKRSY&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421analytics.bmj.com/gtag/js?id=G-LHT0... https://analytics.bmj.com/gtag/js?id=G-LHT0ZJKRSY&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421 — 200 — 194.7 KiB — 255 ms — h2https://www.googletagmanager.com/gtag/js?id=G-8P7810XE1M&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-8P7810XE1M&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421 — 200 — 152.3 KiB — 68 ms — h2https://analytics.bmj.com/gtag/js?id=G-N0KVPL2464&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421analytics.bmj.com/gtag/js?id=G-N0KV... https://analytics.bmj.com/gtag/js?id=G-N0KVPL2464&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421 — 200 — 180.2 KiB — 237 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/otFlat.jsoncookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/otFlat.json — 200 — 3.5 KiB — 23 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/v2/otPcTab.jsoncookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/v2/otPcTab.json — 200 — 14.2 KiB — 23 ms — h2https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/otCommonStyles.csscookie-cdn.cookiepro.com/scripttemp... https://cookie-cdn.cookiepro.com/scripttemplates/202604.1.0/assets/otCommonStyles.css — 200 — 5.1 KiB — 20 ms — h2https://cookie-cdn.cookiepro.com/logos/static/ot_guard_logo.svgcookie-cdn.cookiepro.com/logos/stat... https://cookie-cdn.cookiepro.com/logos/static/ot_guard_logo.svg — 200 — 692 B — 20 ms — h2https://cookie-cdn.cookiepro.com/logos/static/ot_company_logo.pngcookie-cdn.cookiepro.com/logos/stat... https://cookie-cdn.cookiepro.com/logos/static/ot_company_logo.png — 200 — 11.7 KiB — 23 ms — h2https://cookie-cdn.cookiepro.com/logos/static/powered_by_logo.svgcookie-cdn.cookiepro.com/logos/stat... https://cookie-cdn.cookiepro.com/logos/static/powered_by_logo.svg — 200 — 2.8 KiB — 28 ms — h2https://www.google-analytics.com/g/collect?v=2&tid=G-8P7810XE1M&gtm=45je64h1v871065287z876895456za20gzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3r3q2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5a&gdid=dYWJhMj&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=14&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938468~117266400~117384405~118128922&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=CA&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=1200www.google-analytics.com/g/collect?... https://www.google-analytics.com/g/collect?v=2&tid=G-8P7810XE1M&gtm=45je64h1v871065287z876895456za20gzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3r3q2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5a&gdid=dYWJhMj&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=14&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938468~117266400~117384405~118128922&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=CA&en=page_view&_fv=1&_nsi=1&_ss=1&tfd=1200 — 204 — 547 B — 192 ms — h2https://analytics.bmj.com/g/collect?v=2&tid=G-N0KVPL2464&gtm=45he64h1v9174317348z876895456za20kzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3rPq2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5b&gdid=dYWJhMj&ecid=840572213&_fplc=0&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=9&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&ur=&sst.rnd=1196357920.1776797539&sst.gdpr=1&sst.gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&sst.tft=1776797538011&sst.lpc=179606583&sst.navt=n&sst.ude=0&sst.sw_exp=1&_s=1&tag_exp=0~115938466~115938469~117266400&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=DA&en=page_view&_fv=1&_ss=1&gap.gtb=2&ep.article_series_title=null&ep.DOI=null&ep.article-length=not%20article%20page&ep.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&up.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&tfd=1298&richsstsseanalytics.bmj.com/g/collect?v=2&tid... https://analytics.bmj.com/g/collect?v=2&tid=G-N0KVPL2464&gtm=45he64h1v9174317348z876895456za20kzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3rPq2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5b&gdid=dYWJhMj&ecid=840572213&_fplc=0&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=9&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&ur=&sst.rnd=1196357920.1776797539&sst.gdpr=1&sst.gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&sst.tft=1776797538011&sst.lpc=179606583&sst.navt=n&sst.ude=0&sst.sw_exp=1&_s=1&tag_exp=0~115938466~115938469~117266400&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=DA&en=page_view&_fv=1&_ss=1&gap.gtb=2&ep.article_series_title=null&ep.DOI=null&ep.article-length=not%20article%20page&ep.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&up.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&tfd=1298&richsstsse — 200 — 491 B — 104 ms — h2https://analytics.bmj.com/_/service_worker/63b0/sw_iframe.html?origin=https%3A%2F%2Fwww.bmj.com&1p=1analytics.bmj.com/_/service_worker/... https://analytics.bmj.com/_/service_worker/63b0/sw_iframe.html?origin=https%3A%2F%2Fwww.bmj.com&1p=1 — 200 — 1.9 KiB — 89 ms — h2https://analytics.bmj.com/g/collect?v=2&tid=G-LHT0ZJKRSY&gtm=45he64h1v887279588z876895456za20kzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3rPq2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5b&gdid=dYWJhMj&ecid=1900440668&_eu=AAAAAGA&_fplc=0&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=15&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&ur=&sst.rnd=1196357920.1776797539&sst.gdpr=1&sst.gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&sst.tft=1776797538011&sst.lpc=179606583&sst.navt=n&sst.ude=0&sst.sw_exp=1&_s=1&tag_exp=0~115938466~115938469~117266401~117884344&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=DA&en=page_view&_fv=1&_ss=1&gap.gtb=2&ep.article_series_title=null&ep.DOI=null&ep.article-length=not%20article%20page&ep.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&ep.dataTransferred=1.49&up.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&tfd=1391&richsstsseanalytics.bmj.com/g/collect?v=2&tid... https://analytics.bmj.com/g/collect?v=2&tid=G-LHT0ZJKRSY&gtm=45he64h1v887279588z876895456za20kzb76895456zd76895456&_p=1776797538011&gcs=G101&gcd=13q3rPq2q5l1&npa=1&dma_cps=-&dma=1&tcfd=10s5b&gdid=dYWJhMj&ecid=1900440668&_eu=AAAAAGA&_fplc=0&are=1&cid=607046678.1776797539&frm=0&pscdl=denied&rcb=15&sr=800x600&uaa=x86&uab=64&uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&ur=&sst.rnd=1196357920.1776797539&sst.gdpr=1&sst.gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&sst.tft=1776797538011&sst.lpc=179606583&sst.navt=n&sst.ude=0&sst.sw_exp=1&_s=1&tag_exp=0~115938466~115938469~117266401~117884344&dl=https%3A%2F%2Fwww.bmj.com%2F&sid=1776797539&sct=1&seg=0&dt=The%20BMJ%3A%20Leading%20Medical%20Research%2C%20News%2C%20Education%2C%20Opinion&_tu=DA&en=page_view&_fv=1&_ss=1&gap.gtb=2&ep.article_series_title=null&ep.DOI=null&ep.article-length=not%20article%20page&ep.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&ep.dataTransferred=1.49&up.bmj_uuid=6da72bc4-46e3-4962-b9c3-0cc9103d559b&tfd=1391&richsstsse — 200 — 416 B — 112 ms — h2https://www.bmj.com/cdn-cgi/rum?www.bmj.com/cdn-cgi/rum? https://www.bmj.com/cdn-cgi/rum? — 204 — 195 B — 9 ms — h3https://vitals.vercel-insights.com/v1/vitalsvitals.vercel-insights.com/v1/vital... https://vitals.vercel-insights.com/v1/vitals — 200 — 165 B — 28 ms — h2https://www.googletagmanager.com/gtag/destination?id=DC-13070819&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421www.googletagmanager.com/gtag/desti... https://www.googletagmanager.com/gtag/destination?id=DC-13070819&cx=c&gtm=4e64h1&sign=6c57a7885666b1f0824e79ed8919596bee66a6f0f179b4df8c1b91730dab4ff0_20260421 — 200 — 130.0 KiB — 68 ms — h3https://w.soundcloud.com/player/api.jsw.soundcloud.com/player/api.js https://w.soundcloud.com/player/api.js — 200 — 3.5 KiB — 27 ms — h2https://pagead2.googlesyndication.com/ccm/collect?rcb=19&frm=0&ae=g&en=page_view&dl=https%3A%2F%2Fwww.bmj.com%2F&scrsrc=analytics.bmj.com&rnd=1196357920.1776797539&navt=n&npa=1&gdpr=1&gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&ep.ads_data_redaction=0&gdid=dYWJhMj&_tu=CA&gtm=45Fe64h1v76895456za204zd76895456xea&gcs=G101&gcd=13q3r3q2q5l1&dma_cps=-&dma=1&tcfd=10s5b&tag_exp=0~115938466~115938468~117266401~117384406&apve=1&apvf=f&gap.gtb=2&apvc=1&tft=1776797539375&tfd=1473pagead2.googlesyndication.com/ccm/c... https://pagead2.googlesyndication.com/ccm/collect?rcb=19&frm=0&ae=g&en=page_view&dl=https%3A%2F%2Fwww.bmj.com%2F&scrsrc=analytics.bmj.com&rnd=1196357920.1776797539&navt=n&npa=1&gdpr=1&gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA&ep.ads_data_redaction=0&gdid=dYWJhMj&_tu=CA&gtm=45Fe64h1v76895456za204zd76895456xea&gcs=G101&gcd=13q3r3q2q5l1&dma_cps=-&dma=1&tcfd=10s5b&tag_exp=0~115938466~115938468~117266401~117384406&apve=1&apvf=f&gap.gtb=2&apvc=1&tft=1776797539375&tfd=1473 — 200 — 21 B — 54 ms — h3https://thebmj-frontend.bmj.com/next-resources/favicon.icothebmj-frontend.bmj.com/next-resour... https://thebmj-frontend.bmj.com/next-resources/favicon.ico — 200 — 611 B — 14 ms — h2https://ade.googlesyndication.com/ddm/activity/src=13070819;type=counter;cat=allvi0;rcb=9;ord=6639316853540;gdpr=1;gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA;npa=1;u12=https%3A%2F%2Fwww.bmj.com%2F;gdid=dYWJhMj;uaa=x86;uab=64;uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164;uamb=0;uam=;uap=macOS;uapv=10.15.7;uaw=0;pscdl=denied;frm=0;_tu=KFA;gtm=45fe64h1v9181807179z876895456za20gzb76895456zd76895456xea;gcs=G101;gcd=13q3r3q2q5l1;dma_cps=-;dma=1;dc_fmt=8;tcfd=10s5a;tag_exp=0~115938466~115938468~117266400~117884344;epver=2;~oref=https%3A%2F%2Fwww.bmj.com%2F?ade.googlesyndication.com/ddm/activ... https://ade.googlesyndication.com/ddm/activity/src=13070819;type=counter;cat=allvi0;rcb=9;ord=6639316853540;gdpr=1;gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA;npa=1;u12=https%3A%2F%2Fwww.bmj.com%2F;gdid=dYWJhMj;uaa=x86;uab=64;uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164;uamb=0;uam=;uap=macOS;uapv=10.15.7;uaw=0;pscdl=denied;frm=0;_tu=KFA;gtm=45fe64h1v9181807179z876895456za20gzb76895456zd76895456xea;gcs=G101;gcd=13q3r3q2q5l1;dma_cps=-;dma=1;dc_fmt=8;tcfd=10s5a;tag_exp=0~115938466~115938468~117266400~117884344;epver=2;~oref=https%3A%2F%2Fwww.bmj.com%2F? — 302 — 1.2 KiB — 52 ms — h2https://ade.googlesyndication.com/ddm/activity/src=13070819;dc_pre=CLbgudHO_5MDFZnuSQUdWn4Ibw;type=counter;cat=allvi0;rcb=9;ord=6639316853540;gdpr=1;gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA;npa=1;u12=https%3A%2F%2Fwww.bmj.com%2F;gdid=dYWJhMj;uaa=x86;uab=64;uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164;uamb=0;uam=;uap=macOS;uapv=10.15.7;uaw=0;pscdl=denied;frm=0;_tu=KFA;gtm=45fe64h1v9181807179z876895456za20gzb76895456zd76895456xea;gcs=G101;gcd=13q3r3q2q5l1;dma_cps=-;dma=1;dc_fmt=8;tcfd=10s5a;tag_exp=0~115938466~115938468~117266400~117884344;epver=2;~oref=https%3A%2F%2Fwww.bmj.com%2F?ade.googlesyndication.com/ddm/activ... https://ade.googlesyndication.com/ddm/activity/src=13070819;dc_pre=CLbgudHO_5MDFZnuSQUdWn4Ibw;type=counter;cat=allvi0;rcb=9;ord=6639316853540;gdpr=1;gdpr_consent=CQjA2wAQjA2wAAcABBENCbFgAAAAAEPgAChQAAAYsAAAACIAAAAAECAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABAAAAAAAAgAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAaYBk-YJklOgiAJghIyDIhNUEg8UxRCghyA2KWYA6eIKAGXayQh_qBYAAA.YAAACHwAAAAA.IMXQKwAFAAcABAAEUAJgAUgB4gD9AQ4AicBN4C2wF4ALzAZIBGYCckE7ATwgnkCfME-wUXgoyCjkFHgUmgpQClcFLQUvgpiCmQFNIKbAqJBUYFSYKlgqxBVoFXoKwAraBW8CuIFcwK7QV4BXoCvkFfgWHAsTBYsFj4LIgu1BdwGIIMRAxcAA;npa=1;u12=https%3A%2F%2Fwww.bmj.com%2F;gdid=dYWJhMj;uaa=x86;uab=64;uafvl=Not-A.Brand%3B24.0.0.0%7CChromium%3B146.0.7680.164;uamb=0;uam=;uap=macOS;uapv=10.15.7;uaw=0;pscdl=denied;frm=0;_tu=KFA;gtm=45fe64h1v9181807179z876895456za20gzb76895456zd76895456xea;gcs=G101;gcd=13q3r3q2q5l1;dma_cps=-;dma=1;dc_fmt=8;tcfd=10s5a;tag_exp=0~115938466~115938468~117266400~117884344;epver=2;~oref=https%3A%2F%2Fwww.bmj.com%2F? — 200 — 118 B — 31 ms — h2https://pagead2.googlesyndication.com/pagead/ping?e=1pagead2.googlesyndication.com/pagea... https://pagead2.googlesyndication.com/pagead/ping?e=1 — 204 — 20 B — 44 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 1334ms · 1264KB · $18/mo
www.bmj.com
Other
Costly
Execution 222ms
Transfer 23 KB
Monthly Cost $3/mo
Unattributable
Other
Optional
Execution 199ms
Transfer 0 KB
Monthly Cost $3/mo
cookie-cdn.cookiepro.com
Other
Optional
Execution 157ms
Transfer 18 KB
Monthly Cost $2/mo
analytics.bmj.com
Other
Optional
Execution 153ms
Transfer 200 KB
Unused 33%
Monthly Cost $2/mo
cookie-cdn.cookiepro.com
Other
Optional
Execution 108ms
Transfer 131 KB
Unused 48%
Monthly Cost $1/mo
analytics.bmj.com
Other
Optional
Execution 97ms
Transfer 180 KB
Unused 40%
Monthly Cost $1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 97ms
Transfer 188 KB
Unused 70%
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 95ms
Transfer 152 KB
Unused 40%
Monthly Cost $1/mo
analytics.bmj.com
Other
Optional
Execution 82ms
Transfer 195 KB
Unused 40%
Monthly Cost $1/mo
www.bmj.com
Other
Optional
Execution 73ms
Transfer 46 KB
Monthly Cost $1/mo
Google Tag Manager
Tag Manager
Optional
Execution 51ms
Transfer 130 KB
Unused 50%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • www.bmj.com adds 222ms and costs ~$3/month

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

www.bmj.com takes 222ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

70% of securepubads.g.doubleclick.net's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback