Department of Environmental Health Sciences, Yale School of Public Health, New Haven, Connecticut.
Yale Center for Perinatal, Pediatric, and Environmental Epidemiology, Yale School of Public Health, New Haven, Connecticut.
JAMA Netw Open. 2023 Sep 5;6(9):e2335164. doi: 10.1001/jamanetworkopen.2023.35164.
Cerebral palsy (CP) is the most prevalent neuromotor disability in childhood, but for most cases the etiology remains unexplained. Seasonal variation in the conception of CP may provide clues for their potential etiological risk factors that vary across seasons.
To evaluate whether the month or season of conception is associated with CP occurrence.
DESIGN, SETTING, AND PARTICIPANTS: This statewide cohort study examined more than 4 million live births that were registered in the California birth records during 2007 to 2015 and were linked to CP diagnostic records (up to year 2021). Statistical analyses were conducted between March 2022 and January 2023.
The month and season of conception were estimated based on the child's date of birth and the length of gestation recorded in the California birth records.
CP status was ascertained from the diagnostic records obtained from the Department of Developmental Services in California. Poisson regression was used to estimate the relative risk (RR) and 95% CI for CP according to the month or the season of conception, adjusting for maternal- and neighborhood-level factors. Stratified analyses were conducted by child's sex and neighborhood social vulnerability measures, and the mediating role of preterm birth was evaluated.
Records of 4 468 109 children (51.2% male; maternal age: 28.3% aged 19 to 25 years, 27.5% aged 26 to 30 years; maternal race and ethnicity: 5.6% African American or Black, 13.5% Asian, 49.8% Hispanic or Latinx of any race, and 28.3% non-Hispanic White) and 4697 with CP (55.1% male; maternal age: 28.3% aged 19 to 25 years, 26.0% aged 26 to 30 years; maternal race and ethnicity: 8.3% African American or Black, 8.6% Asian, 54.3% Hispanic or Latinx of any race, and 25.8% non-Hispanic White) were analyzed. Children conceived in winter (January to March) or spring (April to June) were associated with a 9% to 10% increased risk of CP (winter: RR, 1.09 [95% CI, 1.01-1.19]; spring: RR, 1.10 [95% CI, 1.02-1.20]) compared with summer (July to September) conceptions. Analyses for specific months showed similar results with children conceived in January, February, and May being at higher risk of CP. The associations were slightly stronger for mothers who lived in neighborhoods with a high social vulnerability index, but no child sex differences were observed. Only a small portion of the estimated association was mediated through preterm birth.
In this cohort study in California, children conceived in winter and spring had a small increase in CP risk. These findings suggest that seasonally varying environmental factors should be considered in the etiological research of CP.
脑瘫（CP）是儿童中最常见的神经运动障碍，但大多数情况下病因仍未得到解释。CP 概念的季节性变化可能为潜在的季节相关病因风险因素提供线索，这些因素在不同季节有所不同。
评估受孕的月份或季节是否与 CP 的发生有关。
设计、设置和参与者：这项全州范围内的队列研究调查了 2007 年至 2015 年期间在加利福尼亚州出生记录中登记的超过 400 万例活产儿，并将其与 CP 诊断记录（截至 2021 年）相关联。统计分析于 2022 年 3 月至 2023 年 1 月进行。
受孕月份和季节是根据儿童的出生日期和加利福尼亚州出生记录中记录的妊娠期长度来估计的。
CP 状况是从加利福尼亚州发展服务部获得的诊断记录中确定的。使用泊松回归来估计 CP 根据受孕月份或季节的相对风险（RR）和 95%置信区间，同时调整了母亲和社区水平的因素。根据儿童的性别和社区社会脆弱性指标进行分层分析，并评估了早产的中介作用。
对 4468109 名儿童（51.2%为男性；母亲年龄：28.3%为 19 至 25 岁，27.5%为 26 至 30 岁；母亲种族和民族：5.6%为非裔美国人或黑人，13.5%为亚洲人，49.8%为任何种族的西班牙裔或拉丁裔，28.3%为非西班牙裔白人）和 4697 名 CP 患儿（55.1%为男性；母亲年龄：28.3%为 19 至 25 岁，26.0%为 26 至 30 岁；母亲种族和民族：8.3%为非裔美国人或黑人，8.6%为亚洲人，54.3%为任何种族的西班牙裔或拉丁裔，25.8%为非西班牙裔白人）进行了分析。与夏季（7 月至 9 月）受孕相比，冬季（1 月至 3 月）或春季（4 月至 6 月）受孕的儿童 CP 风险增加了 9%至 10%（冬季：RR，1.09[95%CI，1.01-1.19]；春季：RR，1.10[95%CI，1.02-1.20]）。对特定月份的分析显示出类似的结果，1 月、2 月和 5 月受孕的儿童患 CP 的风险更高。对于居住在社会脆弱性指数较高的社区的母亲，这种关联更强，但未观察到儿童性别差异。估计的关联只有一小部分通过早产来介导。
在加利福尼亚州的这项队列研究中，冬季和春季受孕的儿童 CP 风险略有增加。这些发现表明，应在 CP 的病因学研究中考虑季节性变化的环境因素。
