Death by external causes—primarily accidents and suicide—take the lives of more than 5 million people each year, and it has evolved into a major health concern on a global scale. External causes also include violence, undetermined causes, and medical procedures.
In Japan, a country boasting one of the highest life expectancies across the globe, a recent study found that external causes take the lives of women 10 years earlier than those by all other causes. The study sought to investigate the association between female reproductive factors, and the risk of external causes of death among middle-aged women in Japan.
The study followed 49,279 women for 20 years; 8477 of the women died, and the researchers collected their death certificates to confirm their causes of death. Of these deaths, 328 were by external causes: 148 by suicide, and 167 by accident. The researchers found that women designated “ever parous” (carrying at least one pregnancy to 24 weeks) had a lower risk of suicide than those designated “never parous.” They also found that parous women who had ever breastfed were much less likely to die by accident.
The study suggests that the decreased risk of suicide in “ever parous” women is consistent with previous studies. They indicate that the presence of a child may significantly deter the decision to commit suicide, especially while the child is dependent.
In addition, researchers found that the lower risk of accidents seen among postmenopausal women may be linked to the protective effect of breastfeeding on osteoporosis, and subsequent fracture occurrences. Osteoporosis can turn a simple fall into a health crisis, ultimately traced back to an accident.
The study concludes that “suicide and accidents are never the consequence of a single cause; a combination of personal, cultural, social, and biological features likely interact with fluctuations in sex hormones among women.” The researchers acknowledge that the reproductive factors they studied are not modifiable, but emphasize that a better understanding could still help to reduce avoidable deaths by self-harm and accidents.
Adara Bochanisis a 2023 PharmD Candidate at the University of Connecticut in Storrs.
Tanaka S, Abe SK, Sawada N.et al.Female reproductive factors and risk of external causes of death among women: The Japan Public Health Center-based Prospective Study (JPHC Study).Sci Rep9, 14329 (2019) doi:10.1038/s41598-019-50890-x