Gender Differences in BMI, Relationship Status, and Weight Control Behaviors Over Time

Abstract

OBJECTIVEThe purpose of this study was to assess how relationship status was associated with BMI and weight control behaviors among diverse college freshmen.METHODSThis is a secondary data analysis of the longitudinal SPARC (Social impact of Physical Activity and nutRition in College) study, which tracked college freshmen during the 2015–2016 year. The current study examines freshmen SPARC participants residing on campus (n=1100; 64.5% female; 51.4% white) at the start and end of the Fall semester. Participants completed surveys that included questions related to relationship status (single vs other) and a number of weight control behaviors. Participants anthropometrics were measured by trained research assistants. Logistic regression was used to examine the cross‐sectional differences between BMI, gender, weight control behaviors, and relationship status for the incoming freshmen at baseline. Linear and logistic regression was used to examine changes over time. All models were stratified by gender, adjusted for Pell grant status and race/ethnicity, and were clustered by dormitories.RESULTSCross‐sectional results showed that at the start of the academic year 31% of students were in a relationship; more females reported being in relationships than males (OR = 1.78, p<0.001). Females with lower BMIs were more likely to be in a relationship (OR = 0.94, p=0.001); there was no difference between male relationship status and BMI (p=0.255). The mean BMI change over time was 0.47 for females and 0.44 for males; the difference in BMI change by gender was not significant (p=0.741). Baseline relationship status was not associated with a change in BMI at T2 (p=0.34 for females; p= 0.26 for males). Females with lower BMI's at the start of the semester were more likely to be in a relationship at the end of the semester, even after adjusting for previous relationship status (OR 0.92, p=0.008); this association was not observed for males (p=0.429). Weight control behaviors did not predict relationship status at T2 (p=0.235 for females; p=0.133 for males). After adjusting for baseline relationship status, no difference between weight control behaviors and BMI change was observed among females (p=0.155). However, after adjusting for baseline relationship status, BMI change for males was significantly less at T2 (p=0.043) if they were reported at least one weight control behavior.CONCLUSIONSGender differences were observed: more females were in relationships than males, BMI was a significant predictor for female relationship status but not male relationship status, and weight control behaviors were associated with a smaller increase in BMI for males but not females. No direct relationship was observed between weight control behaviors and relationship status. This suggests that female freshmen may have more pressure to be in a relationship and to have a low BMI, and that male freshmen may be more successful in weight management than females, independent of relationship status. Future research should address whether BMI change is related to the quality of the relationship, whether other measures of weight status show the same results, and why we are observing gender differences with freshmen weight control behaviors.Support or Funding InformationThis study was supported by the NIH Common Fund from the Office of the Director and the Office of Behavioral and Social Sciences Research, grant number 1DP5OD017910‐01 (PI: M. Bruening). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Health.