{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T15:08:29Z","timestamp":1777648109447,"version":"3.51.4"},"reference-count":40,"publisher":"BMJ","issue":"11","funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Key Research and Development Program, Ministry of Science and Technology, P.R. 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We hypothesised that FA may have a disproportionate effect that alters the sex-specific prevalence of NTDs.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Setting<\/jats:title>\n                    <jats:p>Data from two time points, before (2003\u20132004) and after (2011\u20132016) the start of the supplementation programme, were obtained from a population-based birth defect surveillance programme among five counties in northern China. All live births (28 or more complete gestational weeks), all stillbirths of at least 20 weeks\u2019 gestational age and pregnancy terminations at any gestational age following the prenatal diagnosis of NTDs were included.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Participants<\/jats:title>\n                    <jats:p>A total of 25\u2009249 and 83 996 births before and after the programme were included respectively.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Primary and secondary outcome measures<\/jats:title>\n                    <jats:p>The prevalence of NTDs by sex and subtype, Male:female rate ratios and their 95% CI were calculated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Overall, NTDs were less prevalent among men than among women (rate ratio (RR) 0.92; 95% CI 0.90 to 0.94), so was anencephaly (RR 0.77; 95%\u2009CI 0.73 to 0.81) and encephalocele (RR 0.75; 95%\u2009CI 0.61 to 0.92), while spina bifida showed a male predominance (RR 1.10; 95%\u2009CI 1.05 to 1.15). The overall prevalence of NTDs decreased by 78\/10 000 in men and 108.7\/10 000 in women from 2003 to 2004 to 2011 to 2016. There was a significant sex difference in the magnitude of reduction, being greater in women than men, particularly for anencephaly.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusions<\/jats:title>\n                    <jats:p>The prevalence of NTDs decreased in both sexes after the implementation of a massive FA supplementation programme. While female predominance was observed in open NTDs and total NTDs, they also had a greater rate of decrease in NTDs after the supplementation programme.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.1136\/bmjopen-2018-022565","type":"journal-article","created":{"date-parts":[[2018,11,8]],"date-time":"2018-11-08T23:15:26Z","timestamp":1541718926000},"page":"e022565","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":27,"title":["Sex differences in the prevalence of neural tube defects and preventive effects of folic acid (FA) supplementation among five counties in northern China: results from a population-based birth defect surveillance programme"],"prefix":"10.1136","volume":"8","author":[{"given":"Jufen","family":"Liu","sequence":"first","affiliation":[{"name":"Institute of Reproductive and Child Health, Key Laboratory of Reproductive Health, National Health Commission of the People\u2019s Republic of China, Peking 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Beijing, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nicholas D E","family":"Greene","sequence":"additional","affiliation":[{"name":"UCL Great Ormond Street Institute of Child Health, University College London, London, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Aiguo","family":"Ren","sequence":"additional","affiliation":[{"name":"Institute of Reproductive and Child Health, Key Laboratory of Reproductive Health, National Health Commission of the People\u2019s Republic of China, Peking University, Beijing, China"},{"name":"Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, 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