{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T17:18:53Z","timestamp":1789751933842,"version":"4.0.1"},"reference-count":33,"publisher":"BMJ","issue":"6","license":[{"start":{"date-parts":[[2026,6,22]],"date-time":"2026-06-22T00:00:00Z","timestamp":1782086400000},"content-version":"unspecified","delay-in-days":21,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Open"],"accepted":{"date-parts":[[2026,6,3]]},"published-print":{"date-parts":[[2026,6]]},"abstract":"<jats:sec>\n                    <jats:title>Objectives<\/jats:title>\n                    <jats:p>To evaluate diagnostic equity, feasibility and acceptability of a remote photoplethysmography-based blood pressure screening application among adults with darker skin tones in Nigeria.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Design<\/jats:title>\n                    <jats:p>Prospective observational multisite field evaluation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Three hospitals in Kebbi State, Nigeria.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>Adults with Fitzpatrick skin types V\u2013VI.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Outcome measures<\/jats:title>\n                    <jats:p>Feasibility, agreement, diagnostic accuracy, acceptability, and equity relevant factors including facial tribal markings and internet bandwidth, using automated cuff measurements as the reference standard and a 140 over 90\u2009mm Hg hypertension threshold.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Among 306 enrolled participants, 249 (81.4%) produced usable readings. Agreement was poor (systolic mean absolute error (MAE) 15.4\u2009mm Hg, root mean square error (RMSE) 19.9; diastolic MAE 10.9\u2009mm Hg, RMSE 13.6). Sensitivity for threshold-based systolic and diastolic blood pressure classification was very low (systolic 0.04; diastolic 0.10), with systolic sensitivity 0.00 in Fitzpatrick type VI. Specificity was high (systolic 0.99; diastolic 0.89). Lower internet bandwidth correlated with reading failure (r = \u22120.69 to \u22120.51). While 70% of patients and over 90% of staff rated the tool favourably, technical limitations created a clear perception\u2013performance gap. In an exploratory interaction analysis, Fitzpatrick type VI was associated with higher odds of measurement failure (OR 5.08, 95%\u2009CI 2.41 to 10.72), but there was no clear evidence that facial tribal markings modified this association (interaction OR 0.66, 95%\u2009CI 0.16 to 2.73; p=0.564).<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>Remote photoplethysmography (rPPG)-based blood pressure screening was feasible but showed inadequate performance in this darker-skinned field cohort, with critically low sensitivity. Without algorithmic recalibration for skin tone diversity and improved offline functionality, cloud-dependent rPPG systems deployed without spectrum-balanced validation may risk exacerbating diagnostic inequities in similar settings.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2026-119311","type":"journal-article","created":{"date-parts":[[2026,6,22]],"date-time":"2026-06-22T14:57:13Z","timestamp":1782140233000},"page":"e119311","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":2,"title":["Skin tone and diagnostic equity in contactless blood pressure screening: a prospective observational field evaluation of remote photoplethysmography in Nigeria"],"prefix":"10.1136","volume":"16","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-1535-5962","authenticated-orcid":false,"given":"David","family":"Dasa","sequence":"first","affiliation":[{"name":"Bournemouth University, Poole, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Philip","family":"Davies","sequence":"additional","affiliation":[{"name":"Bournemouth University, Poole, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,6,22]]},"reference":[{"key":"2026090306262052000_16.6.e119311.1","doi-asserted-by":"publisher","DOI":"10.1038\/s41581-019-0244-2"},{"key":"2026090306262052000_16.6.e119311.2","unstructured":"WHO . First who report details devastating impact of hypertension and ways to stop it. 2023. Available: https:\/\/www.who.int\/news\/item\/19-09-2023-first-who-report-details-devastating-impact-of-hypertension-and-ways-to-stop-it"},{"key":"2026090306262052000_16.6.e119311.3","doi-asserted-by":"publisher","DOI":"10.1038\/s41569-021-00559-8"},{"key":"2026090306262052000_16.6.e119311.4","unstructured":"National Institute for Health and Care and C . National guideline, hypertension in adults: diagnosis and management. London National Institute for Health and Care Excellence; 2019."},{"key":"2026090306262052000_16.6.e119311.5","doi-asserted-by":"crossref","first-page":"963","DOI":"10.1111\/jch.14220","article-title":"Prevalence, awareness, treatment, and control of hypertension in Nigeria in 1995 and 2020: A systematic analysis of current evidence","volume":"23","author":"Adeloye","year":"2021","journal-title":"J of Clinical Hypertension"},{"key":"2026090306262052000_16.6.e119311.6","doi-asserted-by":"crossref","DOI":"10.1155\/2012\/960546","article-title":"Hypertension-related admissions and outcome in a tertiary hospital in northeast Nigeria","volume":"2012","author":"Kolo","year":"2012","journal-title":"Int J Hypertens"},{"key":"2026090306262052000_16.6.e119311.7","doi-asserted-by":"crossref","unstructured":"Schmidt B-M , Durao S , Toews I , et al . Screening strategies for hypertension. Cochrane Database Syst Rev 2020;5. doi:10.1002\/14651858.CD013212.pub2","DOI":"10.1002\/14651858.CD013212.pub2"},{"key":"2026090306262052000_16.6.e119311.8","doi-asserted-by":"publisher","DOI":"10.1001\/jama.2020.21669"},{"key":"2026090306262052000_16.6.e119311.9","doi-asserted-by":"crossref","DOI":"10.1136\/bmjgh-2022-009316","article-title":"The global health workforce stock and distribution in 2020 and 2030: a threat to equity and \u201cuniversal\u201d health coverage?","volume":"7","author":"Boniol","year":"2022","journal-title":"BMJ Glob Health"},{"key":"2026090306262052000_16.6.e119311.10","doi-asserted-by":"crossref","first-page":"806","DOI":"10.1161\/HYPERTENSIONAHA.120.16625","article-title":"The 2020 \u201cWHO Technical Specifications for Automated Non-Invasive Blood Pressure Measuring Devices With Cuff\u201d","volume":"77","author":"John","year":"2021","journal-title":"Hypertension"},{"key":"2026090306262052000_16.6.e119311.11","doi-asserted-by":"publisher","DOI":"10.1109\/TBME.2016.2609282"},{"key":"2026090306262052000_16.6.e119311.12","doi-asserted-by":"crossref","first-page":"858","DOI":"10.1007\/s11704-016-6243-6","article-title":"Remote heart rate measurement using low-cost RGB face video: a technical literature review","volume":"12","author":"Rouast","year":"2018","journal-title":"Front Comput Sci"},{"key":"2026090306262052000_16.6.e119311.13","unstructured":"Ba Y , Wang Z , Karinca KD , et al . Overcoming difficulty in obtaining dark-skinned subjects for remote-ppg by synthetic augmentation. arXiv [Preprint] 2021."},{"key":"2026090306262052000_16.6.e119311.14","doi-asserted-by":"crossref","unstructured":"Nowara EM , McDuff D , Veeraraghavan A . A meta-analysis of the impact of skin type and gender on non-contact photoplethysmography measurements. Proceedings of the IEEE\/CVF Conference on Computer Vision and Pattern Recognition Workshops; Seattle, WA, USA, 2020 Available: https:\/\/ieeexplore.ieee.org\/xpl\/mostRecentIssue.jsp?punumber=9142289","DOI":"10.1109\/CVPRW50498.2020.00150"},{"key":"2026090306262052000_16.6.e119311.15","doi-asserted-by":"crossref","DOI":"10.2196\/36340","article-title":"Measurement of Vital Signs Using Lifelight Remote Photoplethysmography: Results of the VISION-D and VISION-V Observational Studies","volume":"6","author":"Heiden","year":"2022","journal-title":"JMIR Form Res"},{"key":"2026090306262052000_16.6.e119311.16","first-page":"155","article-title":"Examining the Influence of Infrastructure Deficit on Economic Activities, Education, and Healthcare in Rural Areas of Nigeria","volume":"9","author":"Ezeudu","year":"2024","journal-title":"Nnamdi Azikiwe Journal of Political Science"},{"key":"2026090306262052000_16.6.e119311.17","unstructured":"Xim . How lifelight works, science. 2021. Available: https:\/\/lifelight.ai\/science"},{"key":"2026090306262052000_16.6.e119311.18","unstructured":"NICE . Lifelight first for monitoring vital signs. London, 2020."},{"key":"2026090306262052000_16.6.e119311.19","doi-asserted-by":"publisher","DOI":"10.1364\/OE.16.021434"},{"key":"2026090306262052000_16.6.e119311.20","doi-asserted-by":"publisher","DOI":"10.1148\/radiol.2015151516"},{"key":"2026090306262052000_16.6.e119311.21","unstructured":"Association for the Advancement of Medical Instrumentation . ANSI\/aami\/iso 81060-2:2019 non-invasive sphygmomanometers part 2: clinical investigation of intermittent automated measurement type. Arlington VA: AAMI; 2019."},{"key":"2026090306262052000_16.6.e119311.22","doi-asserted-by":"crossref","DOI":"10.1093\/eurheartj\/ehad655.2986","article-title":"Prospective clinical validation of a noncontact vital signs measurement smartphone application in emergency department","volume":"44","author":"Niel","year":"2023","journal-title":"Eur Heart J"},{"key":"2026090306262052000_16.6.e119311.23","doi-asserted-by":"crossref","first-page":"787","DOI":"10.1177\/09500170231173591","article-title":"Employment Discrimination against Indigenous People with Tribal Marks in Nigeria: The Painful Face of Stigma","volume":"38","author":"Adisa","year":"2024","journal-title":"Work, Employment and Society"},{"key":"2026090306262052000_16.6.e119311.24","doi-asserted-by":"crossref","first-page":"035004","DOI":"10.1088\/2057-1976\/ab51ba","article-title":"Impact of makeup on remote-PPG monitoring","volume":"6","author":"Wang","year":"2020","journal-title":"Biomed Phys Eng Express"},{"key":"2026090306262052000_16.6.e119311.25","doi-asserted-by":"publisher","DOI":"10.1097\/MBP.0b013e3283360e98"},{"key":"2026090306262052000_16.6.e119311.26","doi-asserted-by":"publisher","DOI":"10.1016\/j.amjhyper.2005.08.021"},{"key":"2026090306262052000_16.6.e119311.27","doi-asserted-by":"publisher","DOI":"10.4103\/0378-6323.45238"},{"key":"2026090306262052000_16.6.e119311.28","doi-asserted-by":"crossref","first-page":"725","DOI":"10.1097\/DSS.0000000000003860","article-title":"Updating the Fitzpatrick Classification: The Skin Color and Ethnicity Scale","volume":"49","author":"Coleman","year":"2023","journal-title":"Dermatol Surg"},{"key":"2026090306262052000_16.6.e119311.29","unstructured":"Federal Government of NIgeria . Nigeria data protection act. Nigeria Federal Republic of Nigeria Official Gazette; 2023."},{"key":"2026090306262052000_16.6.e119311.30","doi-asserted-by":"publisher","DOI":"10.1016\/s0140-6736(86)90837-8"},{"key":"2026090306262052000_16.6.e119311.31","doi-asserted-by":"crossref","first-page":"1289","DOI":"10.1001\/jamadermatol.2013.6101","article-title":"Accuracy of self-report in assessing Fitzpatrick skin phototypes I through VI","volume":"149","author":"Eilers","year":"2013","journal-title":"JAMA Dermatol"},{"key":"2026090306262052000_16.6.e119311.32","doi-asserted-by":"crossref","DOI":"10.1038\/s41746-024-01176-8","article-title":"A survey of skin tone assessment in prospective research","volume":"7","author":"Weir","year":"2024","journal-title":"NPJ Digit Med"},{"key":"2026090306262052000_16.6.e119311.33","doi-asserted-by":"publisher","DOI":"10.1016\/S0022-202X(20)32200-4"}],"container-title":["BMJ Open"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bmjopen-2026-119311","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T13:27:46Z","timestamp":1788442066000},"score":1,"resource":{"primary":{"URL":"https:\/\/bmjopen.bmj.com\/lookup\/doi\/10.1136\/bmjopen-2026-119311"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6]]},"references-count":33,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,6,22]]},"published-print":{"date-parts":[[2026,6]]}},"alternative-id":["10.1136\/bmjopen-2026-119311"],"URL":"https:\/\/doi.org\/10.1136\/bmjopen-2026-119311","relation":{},"ISSN":["2044-6055","2044-6055"],"issn-type":[{"value":"2044-6055","type":"print"},{"value":"2044-6055","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6]]}}}