Body mass index and health-related quality of life

Abstract

Objective: There are conflicting data regarding the association between body mass index (BMI) and health-related quality of life (HRQoL), especially among certain population subgroups and for mental and physical health domains.

Methods: This study analysed the relationship between BMI and HRQoL (Patient-Reported Outcomes Measurement Information System mental and physical health scales) using ordinary least squares regression. Each model allowed for the possibility of a non-linear relationship between BMI and the outcome, adjusting for age, gender, comorbidities, diet and physical activity.

Results: A total of 10,133 respondents were predominantly female (71.7%), White (84.1%), median age of 52.1 years (interquartile range 37.2-63.3) and median BMI of 27.9 (interquartile range 24.0-33.2). In adjusted models, BMI was significantly associated with physical and mental HRQoL (p < 0.001). For physical HRQoL, there was a significant interaction with age (p = 0.02). For mental HRQoL, there was a significant interaction with sex (p = 0.0004) but not age (p = 0.7).

Conclusions: This study demonstrates a non-linear association of variable clinical relevance between BMI and HRQoL after adjusting for demographic factors and comorbidities. The relationship between BMI and HRQoL is nuanced and impacted by gender and age. These findings challenge the idea of obesity as a main driver of reduced HRQoL, particularly among women and with respect to mental HRQoL.

Keywords: Body mass index (BMI); epidemiology; public health; quality of life.

Figure 1

Flow diagram of survey participants. BMI, body mass index; CDRN, Clinical Data Research Network.

Figure 2

Model‐based estimates showing the association between body mass index (BMI) and health‐related quality of life in both physical and mental domains. We show model‐based estimates and 95% confidence intervals for unadjusted models. Subsequent models are partially adjusted, controlling for age, gender, income, education, employment, marital status, race/ethnicity, smoking status, number of people age < 19 years living in the home, history of high blood pressure, history of diabetes, history of high cholesterol and spirituality. Fully adjusted models control for all of the previous covariates, with the addition of diet and physical activity. The F‐tests of the overall association between BMI and quality of life were statistically significant for both physical health quality of life (p < 0.0001) and mental health quality of life (p < 0.0001). Estimates from the partially and fully adjusted models are shown for subjects with the sample median value for age (52) and with values of all other covariates equal to the sample mode. PROMIS, Patient‐Reported Outcomes Measurement Information System.

Figure 3

Associations between body mass index (BMI) and health‐related quality of life (HRQoL), with interations by age and gender. Model‐based estimates showing the association between BMI and HRQoL in both physical and mental domains are shown separately by gender, across a range of age values. Models are adjusted for age, gender, income, education, employment, marital status, race/ethnicity, smoking status, number of people age < 19 years living in the home, physical activity, diet, history of high blood pressure, history of diabetes, history of high cholesterol and spirituality. For physical HRQoL, there was a significant interaction with age (p = 0.02) and a trend towards significance for the interaction with gender (p = 0.0579). For mental HRQoL, there was a significant interaction with gender (p = 0.0004) but not with age (p = 0.7).