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If your mum is overweight, will you be? If she’s had breast cancer, will
you have it too? Here, doctors answer women’s two main concerns. |
WHY WE GAIN WEIGHT
What percentage of obesity cases is inherited?
The role of genes in obesity is an interesting topic. Causes of obesity are polygenic, i.e. many genes are involved. Genetic factors can determine one’s resting metabolic rate, affinity for certain foods (e.g. high fat, high sugar), physical activity habits, and pattern of fat distribution.
While some cases of obesity are clearly a result of pure genetic abnormalities, these tend to occur early in childhood and result in morbid (severe) obesity. The majority of obesity is the result of genetic tendency to weight gain and the environment, with lifestyle (bad habits such as overeating and lack of physical exercise) playing the larger role. If you practice healthy habits, obesity cannot develop even if you have a genetic predisposition. |
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With 53 per cent of Singaporeans having a body mass index at a risk equivalent considered overweight (BMI 23 and above) and 16 per cent at an equivalent considered obese, it is hard to attribute the cause of overweight all to the genes. This suggests that the environment and lifestyle in Singapore is what mainly contributes to obesity.
If your mother is overweight and obese, you will have a higher tendency to gain weight as well. How much of this is because of genetic inheritance and how much of this is because of genetic inheritance and how much of this is because of the family environment and lifestyle is not clearly defined yet at present.
Certain medical conditions like hypothyroidism can also contribute to one’s tendency to weight gain if these medical conditions are inherited as well. Regardless, adopting a healthy lifestyle can certainly overcome these factors, or at least reduce the amount of weight gain.
Is obesity a medical condition or is it a matter of the same household having poor eating habits?
Obesity, once developed, is a chronic medical condition in itself, as it has a tendency to recur (i.e. weight regained after weight loss). It is also a risk factor contributing to the development of many other medical problems, like diabetes, certain cancers, impaired fertility and osteoarthritis of the knees.
The treatment of the latter conditions (except for cancer) needs to take into consideration reducing obesity. However, this should not be confused to the cause and contribution to obesity, which is one’s lifestyle.
The environment of poor eating habits – portion sizes, types of food (high in fat and sugar), combined with lack of physical activity will definitely fuel the development of obesity in most people. This is largely influenced by one’s family environment.
Why do older women get fat?
In general, as an individual grows older, one’s metabolic rate declines. The total amount of physical activity also tends to decline with age. With food intake remaining a constant, the inclination towards weight gain is high. The two other factors contributing to weight gain are pregnancy and menopause.
Can we avoid the same pitfalls?
Certainly! A lot of attention needs to be paid to one’s lifestyle, especially during these crucial periods of life as mentioned above. Maintaining a healthy lifestyle through a balanced diet without consuming too many calories, a good level of physical activity, controlling stress levels, and adequate good quality sleep, is very important. Preventing weight gain throughout life may mean reducing one’s food intake and increasing the level of physical activity as we age. With the decline in estrogen with menopause, weight gain tends to occur in the abdominal area (visceral fat), which can increase one’s risk for diseases like diabetes and heart disease and so is more unhealthy.
However, this can be prevented by reducing food intake and increasing physical activity. There is a suggestion that in certain women, hormone replacement therapy after menopause can also reduce this body-fat gain. |
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CANCER AND GENES
Is breast cancer inherited?
The majority of breast cancers are not inherited. Only about 10-15 per cent of all women with breast cancer are due to an abnormal gene passed on from the previous generation. However, not all who have this gene (gene carriers) will definitely get breast cancer. About 60-80 per cent will develop breast cancer in their lifetime. The breast cancer gene can be passed on from either your mother or father.
The breast cancer gene is also associated with other types of cancer – ovarian cancer and more rarely, colorectal and prostate cancer.
Women who are gene carriers do not have any symptoms – they feel perfectly well. The simplest ways to ascertain if a woman is a likely gene carrier is from her family history.
A significant family history would include having a close relative (mother, sister, father or brother) with breast cancer at an early age (less than 40 years). Having multiple relatives with breast or other related cancers would also arouse the doctor’s suspicion.
Can I take any medicine to prevent breast cancer?
To date there is no effective medication (which does not have any side effects) that can prevent breast cancer. Hence, the next best thing is for regular screening so that if the cancer develops, there is a higher chance of detecting it at an early stage.
Women who are gene carriers should have her breasts checked regularly by a doctor. Breast self examination alone has not been shown to detect early breast cancer. For women below 50 years old, mammography has been proven to be the most effective way of detecting early breast cancer. The addition of an ultrasound of the breast has been shown to improve detection. For younger women (less than 40 years), mammography is less informative and therefore they are better off doing ultrasound. More recently, studies from the US and Europe have shown that MRI (magnetic resonance imaging) of the breast to be useful in detecting breast cancer in high-risk women. |
Contributed by Dr Tan Su-Ming, Changi General Hospital and Dr Tham Kwang Wei, Singapore General Hospital |
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