Cummings David R
Biodemography Soc Biol. 2010;56(2):105-22. doi: 10.1080/19485565.2010.524093.
This study tests whether seasonal differences in the United States and European sunshine is associated with human birth patterns. Birth data are adjusted for 31-day months, leap years, and an annual percentage. Clear observations and birth indices are correlated for European and U.S. cities. With 2-month exposure to clearness, r-values are Chicago (0.63), Bismarck (0.81), Dallas (0.86), Thessaloniki (0.66), and Copenhagen (0.54) and, with 3-month exposure, Amsterdam (0.69). Peak clearness occurs during the autumn for the United States and spring/summer for Europe. Differences in clearness may explain birth pattern differences and reduced U.S. births in the 1930s. Although the effect of vitamin D is plausible, further research is required.
本研究检验了美国和欧洲阳光的季节性差异是否与人类出生模式相关。出生数据针对31天的月份、闰年和年百分比进行了调整。对欧洲和美国城市的清晰观测数据与出生指数进行了关联。在暴露于晴朗天气2个月的情况下，芝加哥的r值为0.63，俾斯麦为0.81，达拉斯为0.86，塞萨洛尼基为0.66，哥本哈根为0.54；在暴露3个月的情况下，阿姆斯特丹的r值为0.69。美国的晴朗天气高峰出现在秋季，欧洲则出现在春夏季。晴朗程度的差异可能解释了出生模式的差异以及20世纪30年代美国出生人数的减少。尽管维生素D的作用看似合理，但仍需进一步研究。
