Written by Dr Victor H H Goh, Professor, Science of Ageing, Department of Obstetrics and Gynaecology, National University of Singapore.
With increasing age, changes in the three major body composition of fat, lean and bone mass in men and women are different. Older women have 12% and 22% respectively, more total body and abdominal fat than younger women. The increases in fat mass in the waist and hip may explain why some older women have a “pear” body shape. With the extreme accumulation of fat mass, women, regardless of age, may present a “barrel” body shape. Such an observation is more prevalent in Western populations than in Singapore.
In contrast, total body fat does not change in older as compared to younger men. Abdominal fat in older men, however, is 7% higher than in younger men, which accounts for the observation of the “Beer” belly in some older men. The increase in fat mass in older men as compared to older women is relatively modest. Per unit fat mass tends to occupy a larger volume than lean mass. Hence, the greater increase in fat mass tends to make older women look relatively bigger than their partners.
Obesity, especially abdominal obesity is higher, by 14 times in older women than in younger women. Our studies have shown that abdominal obesity and not general obesity are associated with a higher risk of several lifestyle illnesses such as diabetes, high blood pressure, cardiovascular diseases, stroke, and sleep apnea, just to name a few. Having these illnesses can further accelerate the rate of ageing in affected women.
Lost of muscle mass and strength is known as sarcopenia. On average, lean mass in women is 35% less than in men. With increasing age, women lose about 4-8% of their total lean mass, leading to a loss of 16-17% of strength.
While total bone mass in women is less, their bone densities are not significantly different from those in men. Reduced bone density and bone integrity can lead to conditions called osteopenia (close to brittle bone) and osteoporosis (brittle bone). These conditions carry a higher risk of fracture.
In older Singaporean women, densities of the spine and hip are 14-16% lower when compared to younger women. As a result, spinal osteoporosis increases from 0.6% to 10.5% and hip osteoporosis from 6.1% to 36.8% in older women. This observation is indicative of a serious bone problem in ageing Singaporean women. Osteoporotic fractures can be fatal.
The loss of muscle and bone mass in ageing may lead to other common muscular-skeletal disorders including women having a back bent at the waist, hunched shoulders, and chronic lower back and neck pains. A more serious issue is osteoarthritis of the knees leading to an exponential increase in total knee replacement surgery done today. Osteoarthritis of the knees, like several other disorders, is not primarily a bone problem. Its genesis begins with the loss of muscle mass and strength of the important muscles in the thighs which results in the inability to hold up the knee joints. Grinding of the bones in the sockets leads to severe wear of the bones in the joints resulting in osteoarthritis.
The problem with many of these muscular-skeletal disorders is that their onset may be early, but the progression is very slow and affected women only realized them when these disorders reach pathological states. Therefore, introducing preventive interventions earlier is much more difficult.
Welcome to our series of articles on ageing! Stay tuned for article 3 focusing on Beyond Menopause: The Importance of Early Healthy Aging Strategies for Women's Health. For a more detailed discourse on how Singaporeans are ageing and what measures can help slow down the rate of ageing, refer to the book “Healthy Ageing – For Feeling Good and Looking Good” by Dr Victor H H Goh.