Prevalence and Predictors of Normal-Weight Obesity among Women

Abstract

The present study aimed to (a) assess normal-weight obesity (NWO) and general obesity prevalence among women of different ages residing in urban areas, (b) evaluate subcutaneous fat thickness (SFT) in women with NWO, (c) establish SFT cutoff points for distinguishing NWO, and (d) explore eating habits linked to NWO. This cross-sectional study with 184 women aged 18–65 with NWO, normal weight without obesity (NWNO), overweight and general obesity included evaluation of body composition, SFT assessment using 2.5 MHz A-mode ultrasound (ISAK protocol, 7 sites) and lifestyle inquiries. The curvilinear relationship between body fat and BMI rendered BMI an unreliable indicator of adiposity in women with normal weight (BMI < 25 kg/m2). Almost 30% of women with a high body fat percentage (BFP ≥ 30%) were misclassified when BMI was used to measure adiposity. The overall obesity prevalence defined by BFP was almost four times higher than that defined by BMI (56.0 vs. 18.0%, p = 1 × 10−4). Women with NWO, overweight and general obesity shared a similar SFT profile and eating habits, setting them apart from those with NWNO. The mean SFT was the most reliable NWO predictor, with a threshold set at 12 mm equal to the 66th percentile. Mean SFT accurately classified 85% of women with NWO. While age did not significantly affect subcutaneous fat accumulation, total fat levels increased with age (R2 = 0.07 and R2 = 0.19, padj = 0.1 and padj = 9 × 10−4). Higher NWO prevalence in middle-aged women was linked to age-related increase in fat mass and decrease in fat-free mass. Engaging in regular physical activity and reducing snack consumption effectively countered age-related changes in body composition (padj < 0.05). Women under 45 years who consumed sweet bakery items, fast food, and snacks more frequently showed higher BFP and NWO status (padj < 0.05). Prevention strategies should focus on monitoring body composition and promoting healthy behaviors, particularly among young women transitioning into adulthood and women over 45 years.