一项发表在国际学术期刊Heliyon上的最新研究表明，夏天出生的女性成年后会相对更加健康。这项研究涵盖了英国大约50万人，而文章作者指出怀孕中间三个月内更加充足的光照--也就意味着维生素D暴露更加充分--或可解释这一现象，但仍需要更多研究进行证实。
根据这项研究结果，出生月份会影响孩子的出生体重，而当女性进入青春期，上述两种因素都会对成年女性的整体健康产生一定影响。研究人员指出子宫内环境不同会导致不同胎儿早期生命出现差异，这会影响胎儿成年后的身体健康程度，而这一效应会对儿童期发育直至进入成年期产生作用。
来自剑桥大学的研究人员领导了该项研究，他们首先研究了出生月份是否会影响出生体重，青春期出现以及成年之后的身高。他们发现夏天出生的儿童出生时的体重稍重，成年后身高更高，并且进入青春期的时间也比冬天出生的儿童更晚。
早先研究已经报道过出生季节不同会带来一些特定影响，比如出生体重以及其他不同健康指标。而领导该项研究的Dr.Perry则认为儿童期生长和发育，包括进入青春期的时间，都是早期生命与成年健康状况之间的重要关联，因此他们才决定对出生月份与健康状况之间的关系进行研究。
研究人员认为夏天和冬天出生的婴儿之间存在的差异可能与母亲孕期接受的光照量有关，而光照量部分决定了母亲受到维生素D暴露的程度。
Dr.Perry这样说道："在将我们的发现转化为健康获益之前，我们还需要弄清楚其中的具体机制，我们认为维生素D暴露是一个非常重要的因素。而这项研究也将鼓励科学家们对生命早期维生素D暴露情况对成年健康状况的影响进行更多长期研究。"
Season of birth is associated with birth weight, pubertal timing, adult body size and educational attainment: a UK Biobank study
Felix R. Daya, Nita G. Forouhia, Ken K. Onga, b, John R.B. Perry
Season of birth, a marker of in utero vitamin D exposure, has been associated with a wide range of health outcomes. Using a dataset of ?450,000 participants from the UK Biobank study, we aimed to assess the impact of this seasonality on birth weight, age at menarche, adult height and body mass index (BMI). Birth weight, age at menarche and height, but not BMI, were highly significantly associated with season of birth. Individuals born in summer (June-July-August) had higher mean birth weight (P = 8 × 10?10), later pubertal development (P = 1.1 × 10?45) and taller adult height (P = 6.5 × 10?9) compared to those born in all other seasons. Concordantly, those born in winter (December-January-February) showed directionally opposite differences in these outcomes. A secondary comparison of the extreme differences between months revealed higher odds ratios [95% confidence intervals (CI)] for low birth weight in February vs. September (1.23 [1.15-1.32], P = 4.4 × 10?10), for early puberty in September vs. July (1.22 [1.16-1.28], P = 7.3 × 10?15) and for short stature in December vs. June (1.09 [1.03-1.17], P = 0.006). The above associations were also seen with total hours of sunshine during the second trimester, but not during the first three months after birth. Additional associations were observed with educational attainment; individuals born in autumn vs. summer were more likely to continue in education post age 16 years (P = 1.1 × 10?91) or attain a degree-level qualification (P = 4 × 10?7). However, unlike other outcomes, an abrupt difference was seen between those born in August vs. September, which flank the start of the school year. Our findings provide support for the 'fetal programming' hypothesis, refining and extending the impact that season of birth has on childhood growth and development. Whilst other mechanisms may contribute to these associations, these findings are consistent with a possible role of in utero vitamin D exposure.