|Year : 2020 | Volume
| Issue : 1 | Page : 2-3
Can waist circumference be a screening tool for obesity?
M Suresh Babu
Deputy Director and Professor of Medicine, JSS Medical College and Hospital, JSSAHER, Mysuru, Karnataka, India
|Date of Web Publication||14-Jan-2020|
Dr. M Suresh Babu
739, E and F Blocks, Kuvempunagar, Mysuru - 570 023, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Babu M S. Can waist circumference be a screening tool for obesity?. APIK J Int Med 2020;8:2-3
It has long been recognized that body mass index (BMI in kg/m 2) is a predictor of morbidity and mortality that are due to numerous chronic diseases, including Type 2 diabetes mellitus (DM), cardiovascular disease (CVD), and stroke. In addition, it has been established that abdominal obesity, assessed by waist circumference (WC), predicts obesity-related health risk, and the weighted evidence indicates that WC coupled with BMI predicts health risk better than does BMI alone. The NIH guidelines indicate that the health risk increases in a graded fashion when moving from the normal-weight through obese BMI categories, and that within each BMI category, men and women with high WC values are at a greater health risk than are those with normal WC values. Premanath et al. in their study on the correlation of WC with anthropometric parameters observed that WC correlated significantly with visceral fat and WC was found to be a useful surrogate measure of visceral fat. The Tromso study on longitudinal analyses of WC changes during the 13-year period from 1994 to 2008 clearly demonstrated that the mean WC increased in both men and women but increased more markedly in younger individuals, and the increase in WC was larger than that can be expected from the increases in BMI and age.
WC and BMI are commonly being used as surrogate measures for abdominal obesity and generalized obesity, respectively. Measuring WC takes less time than measuring height and weight. The procedure can be learned easily, and a measuring tape costs minimal (compared to weighing scale and stadiometer required for BMI measurements). Besides, WC can be self-monitored, and it does not need any calculation, unlike BMI. WC measurement can be used by field workers as preferred single screening tool for detection of overweight or obese individuals for weight management in primary health.
According to the WHO, BMI 25–29.99 kg/m 2 and BMI ≥30 kg/m 2 have been classified as overweight and obese, respectively. Keeping in mind the clustering of cardiovascular risk factors and Type 2 DM at the lower levels of obesity among the Asian Indian population than in the non-Asian Indian populations, the diagnosis of obesity is made at a lower level of weight for height among the Asian Indians with normal BMI: 18.0–22.9 kg/m 2, overweight: 23.0–24.9 kg/m 2, and obesity: >25 kg/m 2. The currently recommended optimal cutoff for WC in India is 90 cm for men and 80 cm for women. The use of optimal WC cutoff points for screening should be population specific, as suggested by most of the researchers.
A study conducted in North Glasgow came to a conclusion that measurement of WC for both men and women could be adopted as a simpler valid alternative to BMI for health promotion, by alerting those at risk of CVD, and as a guide to risk avoidance by self-weight management. Kee et al. in a study conducted in Malaysia recommended WC with appropriate population-specific cutoff as a single screening tool for identifying overweight and obesity and its use by health personnel involved in weight control programs and health promotion activities. However, in several studies in India, researchers have suggested a more stringent cutoff for both BMI and WC, as Indians are more prone to cardiovascular risk factors and metabolic syndrome.,
In a study by Misra et al., it was found that, though in males, a WC cutoff point of 90 cm (sensitivity 90.1% and specificity 83.6%), and in females, a cutoff point of 80 cm (sensitivity 92.3% and specificity 76.8%) was good enough for identifying those with a BMI ≥25 kg/m 2, but it had showed a lower sensitivity (49.7% in males and 50.3% in females) in identifying those with at least one cardiovascular risk factor. In the same study, it was shown, for identifying those with BMI ≥23 kg/m 2, the current WC cutoff had a sensitivity of 78.8% and a specificity of 93.2% for males and a sensitivity of 85.2% and a specificity of 84.9% for females. Midha et al. in their study in Kanpur, India, estimated that the cutoffs for WC for predicting hypertension were ≥83 cm for men and ≥78 cm for women. In the study by Snehalatha et al., WC cutoffs of 85 and 80 in men and women, respectively, showed optimum sensitivity and specificity in identifying those with increased risk of Type 2 DM. In a study (n = 2350) from South India by Mohan et al., the optimal cutoffs for identifying any two risk factors was 87 cm for men and 82 cm for women. In several studies in India, researchers have suggested a more stringent cutoff for both BMI and WC, as Indians are more prone to cardiovascular risk factors and metabolic syndrome. Karmakar et al. found that the sensitivity and specificity of WC ≥90 cm in men for identifying overweight were 78.8% and 75.6%, respectively, whereas those of WC ≥80 cm in women were 80.3% and 44%, respectively, which is fair for a tool to be considered as a good screening tool. The present issue includes a study conducted in a rural area of North Karnataka to estimate the prevalence of obesity in a rural population and to assess the sensitivity and specificity of WC values for identifying obesity. The prevalence of abdominal obesity measured by WC in this study population was 36.08%, whereas the prevalence of obesity by taking BMI of ≥25 kg/m 2 as cutoff was 15.82%. The presently recommended WC cutoff values had a sensitivity of 66.67% and 89.47% in males and females, respectively, to diagnose obesity.
If WC measurements are to be used as a single screening tool for identification of overweight and obesity in Indian adults, a less sensitive WC will leave a large proportion of overweight and obese individuals undiagnosed and thus unaware of the health risk. Therefore, we suggest a higher sensitivity (which also means higher false-positive rate) while minimizing the false-negative rate as much as possible in determining the appropriate WC cutoff point because there is relatively less harm in recommending the false-positive group for weight management. In addition, it will make the false-positive group aware of the risks of further weight gain. More research is needed to be done on larger sample size to establish an optimal WC cutoff value for diagnosing obesity in the Indian population.
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