Sexual orientation and bias in self-reported BMI

Area of Science:

• Public Health
• Epidemiology
• Sociology

Background:

• Accurate body mass index (BMI) measurement is crucial for public health research.
• Self-reported height and weight are commonly used to calculate BMI, but their accuracy across different demographic groups requires investigation.
• Understanding potential disparities in self-reported BMI accuracy among sexual orientation groups is important for equitable health assessments.

Purpose of the Study:

• To assess if sexual orientation influences the accuracy of self-reported body mass index (BMI).
• To determine if weight status modifies any observed differences in BMI reporting accuracy among sexual orientation groups.
• To provide insights into the reliability of self-reported BMI data for diverse populations.

Main Methods:

• Analysis of Wave III of the National Longitudinal Study of Adolescent Health (n = 12,197).
• Gender-stratified multiple linear regression models were used to examine associations.
• Controlled for objectively measured BMI, demographic, health, and behavioral variables.
• Tested for effect modification by objectively measured BMI.

Main Results:

• The general population underestimated their BMI, with significant underestimation observed in both females and males.
• Sexual orientation groups showed minimal differences in reporting accuracy.
• Gay males exhibited significant underreporting of BMI compared to heterosexual males (β = -0.37, P = 0.038).
• No evidence of effect modification by objectively measured BMI was found.

Conclusions:

• Most sexual orientation groups demonstrate consistent underreporting of BMI, lending confidence to comparisons based on self-reported data.
• Gay males' underreporting of BMI may inflate perceived differences compared to heterosexual males.
• Findings suggest that self-reported BMI is largely reliable across sexual orientation groups, with specific attention needed for gay males.