OBESITY – A THREAT TO HEALTH
Obesity has been described as a ‘worldwide epidemic’, and will be a major public health problem in the 21st century. Several countries, including the US, UK and Australia, have reported startling rises in obesity prevalence in the past decade. In Singapore, obesity rates have been more controlled, but still rose from 5.1% in 1992 to 6.8% in 2004.
The concern with excess fat in the body is not simply an obsession with the perfect human form, but rather the myriad of co-morbidities that affect health and wellbeing. Obesity has been linked with an increased risk of diabetes mellitus, coronary heart disease, gallbladder diseases, osteoarthritis, gout, sleep apnoea, and certain cancers.
In 1995, the World Health Organisation (WHO) recommended using the BMI cut-off points of 25 kg/m2 and 30 kg/m2 to identify overweight and obesity, respectively. The benchmarks were adopted internationally and have been in use for the past decade. However, the 1995 WHO report also noted that cut-offs were determined based on studies in predominantly Caucasian populations.
Over the last few years, a number of studies have revealed that Asians have 3 to 5% more body fat when compared to Caucasians with the same BMI (controlled
for gender and age). These studies were carried out among various Asian groups, including Chinese, Malays and Indians in Singapore.
In addition, studies reveal that even at a BMI ofbetween 22 to 24 kg/m2, Singaporean adults experienced elevated risk for recognised cardiovascular risk factors (hypertension, diabetes mellitus, dyslipidaemia). This represents a potentially large group of Singaporeans unaware of, and untreated for, underlying risk factors for heart disease and stroke In 2002, a WHO expert consultation panel met in Singapore to consider this new information.
Drawing from studies done in China, Hong Kong, Indonesia, Japan, Thailand and Singapore, the WHO panel recommended that Asian countries consider redefining their BMI cut-offs for public health action and clinical use. These additional cut-offs would be used for defining the health risk for obesityrelated diseases, as well as to facilitate the development of public health measures, clinical management and assessment of interventions.
The Singapore Ministry of Health has since adopted these recommendations, and included it in the Clinical Practice Guideline for Obesity. According to the
new BMI model for Asians, the ideal BMI range is between 18.5kg/m2 to 22.9kg/m2.
The BMI cut-offs are for adults and should not be applied to children. The higher the BMI is above 23 kg/m2, the greater the health risks. It is also important to note that too low a BMI can lead to a different set of health risks – that of inadequate nutrition leading to deficiency diseases and osteoporosis.
It is important that the new Asian BMI cut-offs be communicated in the context of health risk rather than body image. There is already a significant public misperception that being overweight is a cosmetic rather than a health problem. It is therefore important that healthcare professionals consistently communicate a correct perspective to their patients.
The solution to avoiding the health risks associated with obesity lies in weight loss through increased physical activity and controlled reductions in caloric intake. Those with BMI exceeding 23 kg/m2 should be screened for other cardiac risk factors, especially if they have a family history of heart
disease or diabetes. The Clinical Practice Guideline for Obesity should be used as the primary resource in the management of obesity.
Patients may also enquire about the many commercial slimming solutions that are available. Unfortunately, many of these slimming products lack scientific proof of efficacy, and in some cases makers of such products may make exaggerated advertising claims. Again, health professionals can help dispel misconceptions. For example, some products claim to achieve weight loss without having to reduce caloric intake or increase physical activity. Such claims confer a false sense of security, and consumers may end up not restricting their food intake, leading to weight gain.
Finally, the new BMI cut-offs is a tool for assessing the patient’s health risk for cardiovascular disease. However BMI cut-offs are only a guideline, and health risks lie along a continuum, with higher BMI corresponding to higher health risk. Thus all Singaporeans, even those in the healthy weight range
(18.5 to 22.9 kg/m2), can benefit from engaging in regular physical activity, eating a balanced diet and not smoking.
|Asian BMI cut offs for risk categories|
|BMI (kg/m2)||Health Risk|
|27.5 & above||High risk of developing heart disease, high blood pressure, stroke
|23 to 27.4||Moderate risk of developing the above diseases|
|18.5 to 22.9||Low risk of developing the above diseases|
|Below 18.5||At risk of developing nutritional deficiency diseases and osteoporosis|
The following are some tips to help patients achieve a healthy weight:
- Set a realistic weight goal. The patient can expect to experience improved health benefits simply from losing 5-15% of their body weight;
- Target to lose no more than 0.5 to 1.0 kg a week. Go for long-term sustained weight control instead of short-term, rapid weight loss;
- Diets should be designed to reduce your calorie intake. It is preferable to adopt a diet low in fat and high in fibre from fruits and vegetables;
- Include regular physical activity as part of the weight management programme. Suggest small modifications to the daily routine that incorporate physical activity, such as using the stairs in place of the lift.