Longitudinal Position and Cancer Risk in the United States Revisited
The debate over whether to keep daylight savings time has gained attention in recent years, with interest in understanding how the length of exposure to sunlight may affect health outcomes. In this study, we analyzed cancer incidence rates in counties located in different longitudinal positions within time zones and across time zone borders in the contiguous United States. Using both linear and spatial regression models, we found that differences in cancer rates are not significant within time zones or near time zone borders, which challenges previous research. Furthermore, we examined breast, liver, lung, and prostate cancer rates and found that only breast and liver cancers show an increase in incidence from the eastern border to the west within a time zone, while prostate cancer shows the opposite trend. Our study provides insights into the potential difference on human health incurred by an additional hour of sunlight in the morning versus in the evening, which could inform the ongoing discussions about daylight savings time.
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