Men age faster than women… But, the gap is shrinking.
According to research from the University of Jyväskylä in Finland, men are biologically older than women. Smoking and men’s larger bodies may partially explain the observed sex difference.
Starting in the 20th century, life expectancy in the Western world increased quickly. However, women still have a higher life expectancy than men. For example, in Finland, women typically live five more years than men. The gender gap was most prominent in the 1970s when women’s life expectancy at birth was over ten years greater than men’s. However, this disparity has been rapidly closing in recent years.
According to a newly released study, the difference between the genders can also be observed in biological aging. The researchers analyzed possible biological differences in aging men and women and if lifestyle-related factors may account for any potential discrepancies. The distinctions were considered in both young and old adults.
The researchers used several epigenetic clocks as biological aging measures. Epigenetic clocks allow for studying lifespan-related variables while the subject is still alive. For example, they estimate biological age in years based on DNA methylation levels measured in a blood sample.
The study participants were younger (21‒42) and older (50‒76) sets of adult twins from the Finnish Twin Cohort. Lifestyle-related factors, such as education, body mass index, smoking, alcohol use, and physical activity, were measured using questionnaires.
“We found that men are biologically older than women of the same chronological age, and the difference is considerably larger in older participants,” says Anna Kankaanpää, a doctoral researcher at the Gerontology Research Center and the Faculty of Sport and Health Sciences.
More frequent smoking among men explained the gender gap in aging in older but not in young adult twins. What’s more, men’s larger body size explained a small part of the sex gap in both age groups.
“We observed a sex difference in aging pace, which was not explained by lifestyle-related factors,” says Kankaanpää.
“In our study, we also used a quite rare study design and compared the aging pace among opposite-sex twin pairs. A similar difference was also observed among these pairs of twins. The male sibling was about one year biologically older than his female co-twin. These pairs have grown in the same environment and share half of their genes. The difference may be explained, for example, by sex differences in genetic factors and the beneficial effects of the female sex hormone estrogen on health,” Kankaanpää continues.
The results indicate that the decline in smoking among men partially explains why the sex gap in life expectancy has narrowed in recent decades. They also help to understand lifestyle behaviors and sex differences related to biological aging and life expectancy.
Academy researcher Elina Sillanpää lead the AGE-X research project. The project was conducted at the Faculty of Sport and Health Sciences, the University of Jyväskylä in co-operation with the Institute for Molecular Medicine Finland (FIMM), the University of Helsinki, and the Methodology Center for Human Sciences, University of Jyväskylä.
Sources:
https://time.com/5538099/why-do-women-live-longer-than-men/
https://www.census.gov/content/dam/Census/library/publications/2020/demo/p25-1145.pdf
https://pubmed.ncbi.nlm.nih.gov/34752604/