Researchers from Harvard T.H. Chan School of Public Health, Brigham and Women's Hospital, and Medical University of Vienna discovered a link between birth season and heart disease risk.
Previous studies in the Northern Hemisphere consistently associated spring and summer births with higher mortality risks, while the opposite held true south of the equator. However, these studies failed to adequately control for factors like family medical history, economic status, and socioeconomic position.To overcome these limitations, the researchers utilized data from 117,000 registered nurses enrolled in the Nurses' Health Study. Participants were aged 30 to 55 at the study's outset and completed detailed health and lifestyle questionnaires every two years. During follow-up, 43,248 deaths occurred, including 8,360 from cardiovascular disease, with cause of death determined through death certificates and medical records.
Unlike previous studies, this research found no significant association between birth season and overall mortality. However, after accounting for family medical history and socioeconomic factors, it revealed that women born in spring and summer had increased cardiovascular disease mortality compared to those born in autumn.
Published in the British Medical Journal, the study suggests these disparities may stem from seasonal variations in diet, air pollution levels, and exposure to sunlight during prenatal and early life stages.