Assessing the Risk of Normal Weight Obesity in Korean Women across Generations: A Study on Body Composition and Physical Fitness

Normal weight obesity (NWO) refers to a condition in which the body mass index falls within the normal range, but the percent of body fat is excessive. Although there are reports of a high prevalence of cardiovascular and metabolic diseases in NWO, analyses regarding physical fitness have been lacking. Therefore, the purpose of this study was to analyze the age-related prevalence of NWO and to examine physical fitness across generations. Our study utilized a dataset comprising 119,835 participants for analysis. The prevalence of NWO across ages was examined using cross-tabulation analysis. For body composition and physical fitness, medians and group differences were assessed by generation through Kruskal-Wallis and Bonferroni post hoc tests. Additionally, univariate logistic regression was adopted to analyze the odds ratio. The prevalence of NWO in Korean women was 18.3%. The fat-free mass of the NWO group was consistently lower than that of both the group with normal body mass indexes (Normal) and obese body mass indexes (Obesity) across all generations. Additionally, the waist circumference and blood pressure were greater in the now group than in the Normal group. When considering maximal strength, muscle endurance, power, balance, and coordination, the NWO group exhibited lower levels compared to the Normal group. The NWO group showed lower muscle mass than both the Normal and Obesity groups, resulting in significantly reduced physical fitness compared to that of the Normal group, similar to the Obesity group. This condition may increase not only the risk of posing a potentially more serious health concern than obesity but also the risk of falls in elderly people. Therefore, based on this study, it is crucial to not only define obesity using BMI criteria but also to diagnose NWO. Public health policies and preventive measures must be implemented accordingly.