Finnish study finds men age faster than women

Finnish researchers have found that men are biologically older than women, with the observed sex difference partially (but not entirely) explained by men’s more frequent smoking and larger body size. Their results have been published in The Journals of Gerontology: Series A.

In Finland, women currently live on average five years longer than men — a gap that has narrowed somewhat since the 1970s, when life expectancy at birth was almost 10 years higher for women than for men. The new study set out to investigate whether there are differences in biological aging between men and women, and whether these potential differences can be explained by lifestyle-related factors.

The research was carried out via a collaboration between the University of Jyväskylä and the University of Helsinki. The subjects were younger (21‒42 years) and older (50‒76 years) adult twins from the Finnish Twin Cohort. Lifestyle-related factors including education, body mass index, smoking, alcohol use and physical activity were measured using questionnaires.

Several epigenetic clocks were used as measures of biological aging. Epigenetic clocks enable studying lifespan-related factors during an individual’s lifetime, providing an estimate for biological age in years using DNA methylation levels determined from a blood sample.

“We found that men are biologically older than women of the same chronological age, and the difference is considerably larger in older participants,” said Anna Kankaanpää, a doctoral researcher at Jyväskylä’s Gerontology Research Center and the Faculty of Sport and Health Sciences.

More frequent smoking among men explained the sex gap in aging in older but not in young adult twins. In addition, men’s larger body size explained a small part of the sex gap in both age groups. However, Kankaanpää said the researchers also observed a sex difference in aging pace “which was not explained by lifestyle-related factors”.

“In our study, we also used a quite rare study design and compared aging pace among opposite-sex twin pairs,” Kankaanpää said. “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 oestrogen on health.”

The results help to understand lifestyle behaviours and sex differences related to biological aging and life expectancy, with the decline in smoking among men playing a particular part in why the gap in life expectancy has narrowed in recent decades.

Image credit: iStock.com/PeopleImages

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