An Australian study shows that women – but not men – with more abdominal fat are less at risk of bone fracture. This may explain why global rates of fracture are declining at the same time as obesity is increasing.
Abdominal fat is an important risk factor for diabetes and cardiovascular disease, and the authors of the study are by no means recommending that women should gain abdominal fat to protect their bones.
While they do not yet have the data to prove it, the authors believe that the protective effect of abdominal fat in women probably relates to higher levels of oestrogen. Women with more abdominal fat tend to have higher levels of oestrogen, which protects against bone loss, and therefore fracture risk.
The data come from the ongoing Dubbo Osteoporosis Epidemiology Study (DOES), initiated in mid-1989 in the city of Dubbo, about 400 km northwest of Sydney.
The current study examined 1126 participants, 360 men and 766 women, over age 50, recruited to DOES after 2000, when whole body density scanning began. The findings revealed that those women in the top 25% of higher abdominal fat mass had a 40% lower risk of fracture than those with a lower abdominal fat mass. Put another way, each 1 kg less of abdominal fat in women increases their risk of fracture by 50%. There was no such trend seen in men.
Authors Dr Shuman Yang and Professor Tuan Nguyen from Sydney’s Garvan Institute of Medical Research have published their findings, now online in the Journal of Clinical Endocrinology.
“The prevalence of obesity in Australia is not as high as in the US, so our findings relate to ‘moderate’ abdominal obesity when discussed in a global context,” said project leader Professor Tuan Nguyen.
“This study appears to be consistent with the fact that obesity levels are rising worldwide and at the same time fracture incidence is decreasing.”
Source: The Garvan Institute of Medical Research