Unintentional weight loss: Most risk factors do not differ between individuals with a healthy weight and those with overweight or obesity

Objectives Unintentional weight loss (UWL) is an important clinical indicator of malnutrition risk. Risk factors for UWL may differ by body size, measured by body mass index (BMI), and identifying at-risk individuals can be challenging in those with overweight/obesity. Methods Data from ∼125 000 adults (≥18 y) in the Dutch Lifelines cohort were analyzed to examine whether associations between 21 potential risk factors spanning sociodemographic, psychological stress, disease, dietary, and quality-of-life domains and UWL differ by BMI group. Participants were classified as having a healthy weight (45.8%) or overweight/obesity (54.2%). Multivariable Poisson regression models estimated prevalence ratios for UWL, with sensitivity analyses to test robustness. Statistical significance was set at P < 0.05. Results UWL was reported by 4.9% of participants with a healthy weight and 2.7% of those with overweight/obesity. Positive associations with UWL were observed for female sex, (healthy-weight group only), absence from work due to disease, psychological stress in the past year, chronic obstructive pulmonary disease, depression, and poor quality-of-life indicators (physical functioning, perceived health, emotional well-being, vitality, and social functioning). Effect modification by BMI was suggested for 10 risk factors (P < 0.1), with associations generally more pronounced in the healthy-weight group. After sensitivity analyses, only higher educational attainment, psychological stress in the past year, and poor physical functioning retained significant modification. Conclusions Most risk factors for UWL were consistent between BMI groups. Differences in higher educational attainment, psychological stress in the past year, and physical functioning suggest that although the factors are similar, their impact may differ by BMI.