Birth Month, Birth Season, and Overall and Cardiovascular Disease Mortality in US Women: Prospective Cohort Study

Details

• Personal Author:
  Devore EE ; Grodstein F ; Schernhammer ES ; Strohmaier S ; Zhang Y
• Description:
  Objectives: To evaluate the associations between birth month, birth season, and overall and cardiovascular disease mortality, and to examine the role of familial and socioeconomic factors in these associations. Design: Prospective cohort study. Setting: Nurses' Health Study, established in 1976, an ongoing prospective cohort study in the United States. Participants: Female registered nurses who reported information on date of birth at study enrolment (n=116 911, 1976- 2014, followed for 38 years). Exposure: Birth month and astronomical birth season (based on solstices and equinoxes as boundaries of the season categories). Main outcome measures: Age and various multivariable adjusted hazard ratios and 95% confidence intervals for the association between birth months (using November as the reference), astronomical birth season (using autumn as the reference), and overall and cardiovascular disease specific mortality were assessed using Cox proportional hazards models. Results: Among study participants, 43 248 overall deaths were documented during 4 136 364 person years of followup since enrolment, including 8360 cardiovascular disease related deaths. In fully adjusted multivariable analyses, no significant association was observed between birth month, birth season, and overall mortality. Compared with women born in November, increased cardiovascular disease mortality was observed among those born from March to July (hazard ratio for March, 1.09, 95% confidence interval 0.98 to 1.21; April, 1.12, 1.00 to 1.24; May, 1.08, 0.98 to 1.20; June, 1.07, 0.96 to 1.19; and July 1.08, 0.98 to 1.20). Those born in April had the highest cardiovascular disease mortality, and those born in December had the lowest (December, 0.95, 0.85 to 1.06). The relative difference between the lowest and highest risk month was 17.89%. Women born in spring (1.10, 1.04 to 1.17) and summer (1.09, 1.03 to 1.16) had a higher cardiovascular disease mortality than women born in the autumn. Adjustment for familial and socioeconomic factors did not change these results. The relative difference between the lowest and highest risk season was 10.00%. Conclusion: Participants born in the spring and summer (especially those born in March-July) had a slight but significant increase in cardiovascular disease specific mortality. However, no seasonal birth month effect was observed among women for overall mortality. Familial and socioeconomic factors did not appear to alter these associations. Further studies are required to confirm these findings and reveal mechanisms of these seasonal birth month effects in cardiovascular disease mortality. [Description provided by NIOSH]
• Subjects:
  Cardiovascular Diseases Cardiovascular System Cohort Studies Family Mortality Occupational Health Risk Assessment Risk Factors Safety Women
• Keywords:
  Analytical Models Cardiovascular Disease Cardiovascular System Disease Cohort Studies Families Hazards Heart Disease Humans Mortality Data Risk Factors Seasonal Factors Socioeconomics Sociological Factors Statistical Analysis

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• ISSN:
  0959-8138
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  Massachusetts ; OSHA Region 1
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  367
• NIOSHTIC Number:
  nn:20058130
• Citation:
  BMJ 2019 Dec; 367:l6058
• Contact Point Address:
  Eva S. Schernhammer, Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
• Email:
  eva.schernhammer@channing.harvard.edu
• Federal Fiscal Year:
  2020
• Performing Organization:
  Brigham and Women's Hospital, Inc., Boston, Massachusetts
• Peer Reviewed:
  True
• Start Date:
  20100801
• Source Full Name:
  BMJ: British Medical Journal
• End Date:
  20190831
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1e4a425466c60d7db30da78fb468b7d76fa167b38b21713c17f212b67a9db0436cde8189e5e8245d75bd6fc57eb62da6230c2bd616d04813794814809f808463
• Download URL:
  https://stacks.cdc.gov/view/cdc/221272/cdc_221272_DS1.pdf
• File Type:
  [PDF - 1.73 MB ]