Scientists are discovering several new ailments triggered by air pollution, and a new study suggests that air pollution is another factor that tips the scale in mid-life women's weight, body mass index, waist circumference and body fat.

Researchers from the University of Michigan in the US found that exposure to air pollution was linked with higher body fat, higher proportion fat and lower lean mass among midlife women.

For instance, body fat increased by 4.5 per cent, or about 2.6 pounds, according to the study published in the journal Diabetes Care.

"Women in their late 40s and early 50s exposed long-term to air pollutiona" specifically, higher levels of fine particles, nitrogen dioxide and ozone a" saw increases in their body size and composition measures," said Xin Wang, epidemiology research investigator at the university's School of Public Health.

Data for the study came from 1,654 white, Black, Chinese, and Japanese women from the 'Study of Women's Health Across the Nation'.

These women, whose baseline median age was nearly 50 years, were tracked from 2000 to 2008.

Researchers explored the interaction between air pollution and physical activity on body composition.

High levels of physical activity was an effective way to mitigate and offset exposure to air pollution, the research showed.

"Since the study focused on midlife women, the findings can't be generalised to men or women in other age ranges," Wang said.

Obesity has been a major global health issue in recent decades as more people eat unhealthy diets and fail to exercise regularly. (AS/IANS)