Using data provided by the Indiana State Department of Vital Statistics, this study examines the mortality effects of daylight saving time observance using the April 2006 expansion of daylight saving time in Indiana as a natural experiment. The expansion of daylight saving time to all Indiana counties lowered the average mortality rate in the treatment counties during the months in which daylight saving time was observed. Stratified demographic analyses indicate that daylight saving time reduced mortality among males, females, and whites, but only among those aged 65 years and older. Specific-cause analysis indicates that daylight saving time lowered mortality primarily via reduced cancer mortality. The results of this study suggest a novel solar UVB-vitamin D mechanism could be responsible for the reduction in treatment county mortality following the expansion of daylight saving time in Indiana.

利用印第安那州生命统计部提供的数据，本研究使用2006年4月印第安纳州夏令时的扩展作为自然实验，检验了夏令时遵守的死亡率影响。将夏令时扩展到印第安纳州的所有县，可以在观察到夏令时的月份中降低治疗县的平均死亡率。分层的人口统计分析表明，夏时制可以降低男性，女性和白人的死亡率，但仅适用于65岁以上的人群。特定原因分析表明，夏时制主要通过降低癌症死亡率来降低死亡率。