Prevalence of Obesity and the Relationship between the Body Mass Index and Body Fat: Cross-Sectional, Population-Based Data

Abstract

BackgroundAnthropometric measures such as the body mass index (BMI) and waist circumference are widely used as convenient indices of adiposity, yet there are limitations in their estimates of body fat. We aimed to determine the prevalence of obesity using criteria based on the BMI and waist circumference, and to examine the relationship between the BMI and body fat.Methodology/Principal FindingsThis population-based, cross-sectional study was conducted as part of the Geelong Osteoporosis Study. A random sample of 1,467 men and 1,076 women aged 20–96 years was assessed 2001–2008. Overweight and obesity were identified according to BMI (overweight 25.0–29.9 kg/m2; obesity ≥30.0 kg/m2) and waist circumference (overweight men 94.0–101.9 cm; women 80.0–87.9 cm; obesity men ≥102.0 cm, women ≥88.0 cm); body fat mass was assessed using dual energy X-ray absorptiometry; height and weight were measured and lifestyle factors documented by self-report. According to the BMI, 45.1% (95%CI 42.4–47.9) of men and 30.2% (95%CI 27.4–33.0) of women were overweight and a further 20.2% (95%CI 18.0–22.4) of men and 28.6% (95%CI 25.8–31.3) of women were obese. Using waist circumference, 27.5% (95%CI 25.1–30.0) of men and 23.3% (95%CI 20.8–25.9) of women were overweight, and 29.3% (95%CI 26.9–31.7) of men and 44.1% (95%CI 41.2–47.1) of women, obese. Both criteria indicate that approximately 60% of the population exceeded recommended thresholds for healthy body habitus. There was no consistent pattern apparent between BMI and energy intake. Compared with women, BMI overestimated adiposity in men, whose excess weight was largely attributable to muscular body builds and greater bone mass. BMI also underestimated adiposity in the elderly. Regression models including gender, age and BMI explained 0.825 of the variance in percent body fat.Conclusions/SignificanceAs the BMI does not account for differences in body composition, we suggest that gender- and age-specific thresholds should be considered when the BMI is used to indicate adiposity.

Characteristics of Female Nonagenarian Participants in an Observational Health Study

“…The BMI generally underestimates adiposity in the elderly who exhibit age-related losses of musculoskeletal tissue [17]. Despite the likely under-estimation of the obese group, there was a greater proportion of women with BMI >30.0 kg/m 2 in the group lost to follow-up.…”

¿Es la grasa abdominal subcutánea un predictor de la variabilidad cardíaca en hombres con bajo riesgo metabólico?

“…Varios estudios han mostrado que el IMC puede tener baja sensibilidad para la detección de bajo peso y sobrepeso/obesidad, especialmente en hombres, en personas con buen desarrollo muscular y en edad avanzada [26][27][28][29] . El porcentaje de grasa y perímetro abdominal son indicadores de adiposidad total, que sin embargo, están influenciados por la adiposidad abdominal 30 .…”

Impact of Body Mass Index on Outcomes in Cardiac Surgery

“…However, BMI has certain inherent limitations, including not being able to identify differences in body composition and distribution of body fat. 40 BMI also does not quantify visceral adipose tissue, which may be the cornerstone in the obesity-associated pathophysiologic processes. It is possible to skew the results if BMI is used as the sole measure of obesity without adjusting for the other indices of adiposity (eg, waist-to-hip ratios, quantification of visceral fat mass).…”