Central obesity has been shown to be associated with an increased risk of diabetes. Various anthropometric measurements like BMI, WC, W/H, and ICO have been related to metabolic complications.[9
] The purpose of this analysis was to study the role of NC as a measure of obesity and to compare it between diabetics and non-diabetics.
The present study has shown a significant increase in NC in diabetics compared to non-diabetics. NC is reported to be positively associated with glycemic status, W/H, and BMI.[10
] The present study showed positive correlation of NC with BMI, WC, W/H, and ICO (P
< 0.01). Studies have also shown that NC has surpassed other anthropometric measurements as a powerful marker of both visceral adipose tissue (VAT) and insulin resistance.[11
In our study, NC of >36 cm in diabetics and >37 cm in non-diabetics was the best cutoff value to determine subjects with central obesity. Another study reports that large NC is related to the presence of sleep apnea, diabetes, and hypertension.[12
Upper body SC fat, as estimated by NC, may confer risk above and beyond VAT. Anatomically, upper body SC fat is a unique fat depot located in a separate compartment, compared with VAT. Various studies indicate that diabetics have a relative preponderance of adipose tissue in various regions of the upper body. Upper body SC fat is responsible for a much larger proportion of systemic free fatty acid release than visceral fat, particularly in obese individuals, and is lipolytically more active than lower body adipose tissue. Lipolytic activity of upper body fat may mediate this relationship with lipid metabolism and glucose homeostasis. Insulin resistance relates better with SC truncal fat compared to intraperitoneal fat.[13
] Central obesity, particularly high levels of upper body fat, is associated with adverse metabolic outcomes such as insulin resistance, diabetes, hypertension, and elevated triglycerides, whereas individuals with lower body obesity tend to have lower levels of these adverse metabolic outcomes. SC fat plays a major role in obesity-related insulin resistance in men.[14
As there is a high correlation between NC and BMI, WC, ICO, and W/H, and also NC is more in diabetics, which indicates more of regional adiposity is present, the diabetic subjects require a comprehensive evaluation of their overweight and obesity. Upper body SC fat is a novel, easily measured adipose depot, which is an important predictor of diabetic risk. The study of this depot may lead to a better understanding of the differential effects of adiposity in an individual.
Other anthropometric measures have their own limitations. BMI does not account for factors such as body fat distribution, specifically abdominal obesity, and cannot distinguish between lean and fat body mass.[15
] WC has its own disadvantages as subjects are required to wear thin clothes during the measurement, so that the thickness of clothing does not influence the result. The measurement is typically conducted before eating and after emptying bladder. Subjects should be asked to breathe normally and at the time of the measurements asked to breathe out gently. So, it involves discomfort to the subject. W/H and ICO are dependent on WC.
Thus, NC is a better potential clinical screening tool for predicting overweight and obesity; it can be used as an inexpensive straightforward test with less consumption of time.