Womens Health (Lond). 2026 Jan-Dec;22:17455057261455585. doi: 10.1177/17455057261455585. Epub 2026 May 27.
ABSTRACT
Obesity is a global health concern linked to prediabetes, hypertension, sarcopenia, osteoporosis, and cardiovascular disease. However, body mass index (BMI) has limited sensitivity, misclassifying over half of individuals with excess adiposity as having normal weight. Growing evidence identifies a subgroup with normal BMI (18.5-24.9 kg/m2) but elevated body fat (>25% in men, >30% in women), termed normal weight obesity (NWO). Women are at a two-to six-fold higher risk of developing NWO compared to men. To investigate this, an expert review of the literature was conducted utilizing PubMed, Scopus, and Google Scholar to explore the impact of excess adiposity in the context of NWO, emphasizing female physiology across the lifespan and its influence on skeletal muscle and bone health. Many women with NWO remain unaware of underlying hormonal or menstrual dysregulation until challenges arise with fertility or during mid-life transitions. Metabolic disturbances during perimenopause occur independently of obesity but are likely worsened by excess adiposity despite a normal BMI. In postmenopause, the shift from estradiol to estrone and overall estrogen reduction accelerates bone resorption, leading to declines in bone density and strength, and increased fracture risk. Genetic variations in fat distribution, lean mass, and body proportions further modify disease risk among racial and ethnic groups. In women, increased adipose tissue often occurs in the hips and gluteal regions, predisposing to fatty acid infiltration within muscle (myosteatosis), which has been associated with reduced muscle quality outcomes (e.g. muscular strength) and increased falls in older adults. Increasing skeletal muscle mass may improve adiponectin levels, supporting metabolic health, while leptin dysregulation promotes lipid accumulation and inflammation. Higher adiposity, as seen in NWO, impairs bone microstructure and increases fragility through inflammatory pathways. In conclusion, NWO is an underrecognized yet clinically significant condition that elevates women's risk for metabolic, hormonal, muscoskeletal dysfunction despite a normal BMI.
PMID:42202138 | DOI:10.1177/17455057261455585