Predictive Effects of Obesity on Cancer Incidence in Middle-aged and Older Adults: A Panel Analysis Using KLoSA Data

Objectives: Cancer remains the leading cause of death worldwide, and as the proportion of older adults increases, the public health burden from cancer is expected to grow. This study aimed to investigate predictors of cancer among middle-aged and older adults in Korea, with a particular focus on obesity. Methods: Using 15 years of data from Korean Longitudinal Study of Aging (2006-2020), we first applied the Least absolute shrinkage and selection operator (Lasso) to baseline data to identify relevant predictors of cancer incidence. Subsequently, we conducted the logistic regression analyses to estimate the effect of underweight, overweight, and obesity statuses on the probability of developing cancer, controlling for individual characteristics identified as relevant by the Lasso. Results: Following individuals who were cancer-free at baseline over a 15-year period, we found that obesity (BMI≥25) at baseline was a significant predictor of cancer incidence occurring two to fourteen years later, even after adjusting for other predictive factors. Robustness checks confirmed that baseline obesity, even after controlling for obesity measured at various time points, remained a consistent predictor of cancer diagnosed two to twelve years later. Additionally, underweight status (BMI<18.5) was also associated with a significantly increased risk of cancer incidence in later years. Conclusions: These findings highlight the predictive effects of obesity on cancer incidence in both short- and long-term perspectives and suggest that maintaining a healthy weight range may reduce cancer risk. The results underscore the importance of weight management as a key strategy in cancer prevention for aging populations.