Objective

We investigate how alcohol use and friendship co-evolve during students' transition to university. We discern effects of peer influence from friend selection based on alcohol use, whether such effects vary in strength across the school year, and whether alcohol has different effects on friendship formation versus friendship maintenance.

Method

We gathered data on friendships, alcohol use, and binge drinking from 300 residence hall students (71% female) at a large, public U.S. university. Surveys were conducted at four time points during the 2015-2016 academic year. We used a stochastic actor-oriented model to test whether alcohol use was influenced by one's friends, while simultaneously testing for friend selection based on alcohol use and related network processes.

Results

Students were 7.0 times more likely to drink alcohol weekly if all versus none of their friends drank weekly and 6.8 times more likely to binge drink when all versus none of their friends engaged in binge drinking, after we controlled for friend selection. Alcohol use differentially affected friendship creation and maintenance in a complex manner: (a) weekly drinkers were more likely to form new friendships and dissolve existing friendships than nondrinkers and (b) similarity on drinking fostered new friendships but had no effect on friendship persistence.

Conclusions

Friends influence one another's weekly drinking and binge drinking, whereas conversely, alcohol use contributes to both friendship formation and friendship instability.

Objective

To examine if first-year roommates made similar meal plan decisions.

Methods

Residence information for 1186 first-year students (N = 593 roommate pairs) and 559 floormates was obtained for the 2015-2016 academic year. Linear generalized estimating equations (GEEs) were used to examine if the number of meals students used over the semester was higher if their roommate used their meal plan more frequently. A logistic GEE examined joint meal plan usage between students and roommates for each month of the semester. To determine if residence, rather than roommate, explained the results, a simulation was conducted by randomly assigning the floormates to a same-sex roommate.

Results

The number of meals students used in spring was higher if the students' roommate had used more meals in spring, even after controlling for the number of meals students used in fall (Female: β = 0.07, 99% CI = 0.00, 0.13; Male: β = 0.10, 99% CI = 0.02, 0.18). Students were more likely to use a meal with their roommate if they were on the same meal plan (Female: OR = 1.61, 99% CI = 1.27, 2.04; Male: OR = 1.57, 99% CI = 1.09, 2.25), and less likely after the first month of being roommates (Female: OR = 0.57-0.25; Male: OR = 0.50-0.22; p < 0.001). The simulation analysis indicated these findings were not due to shared residence.

Discussion

Students' meal plan choices were associated with their roommates' meal plan choices. Roommates' joint meal plan usage was highest at the start of the year. Strategic roommate pairings may result in students using their meal plan more. Further research should determine the extent of roommate influence on students' diet.

College students and their friends become more similar in weight status over time. However, it is unclear which mediators explain this relationship. Using validated survey measures of diet, physical activity, alcohol intake, sleep behaviors, mental health, and food security status, we take a comprehensive look at possible factors associated with excess weight gain that may explain friends' convergence on body mass index (BMI), waist circumference, waist to hip ratio, and waist to height ratio over time. We use linear mixed models applied to a longitudinal dataset of first-year college students to examine whether these variables satisfy two criteria for potential candidate mediators of friends' influence on anthropometrics-cross-sectional similarity among friends (n = 509) and longitudinal associations with increasing anthropometrics (n = 428). While friends were similar on some survey measures (such as dining hall use, home cooked meal consumption, fruit intake, alcohol intake, hours of sleep, and stress). Only dining hall use and stress emerged as potential explanations for why friends' BMI and anthropometric change may be similar. Given that only a few variables satisfied the two criteria as potential mediators, future research may need to consider alternative measurement approaches, including real-time assessments, objective measurements, and alternative factors causing the convergence of friends' and college students' body size over time.

Some researchers have proposed the prevalence of food insecurity among college students is high due to students' meal plans providing insufficient meals. The association between college students' food security status and their meal plans have not yet been examined. In this study, United States (US) first year college students (N = 534) self-reported their food security status in the Fall 2015 and/or Spring 2016 semester(s). Objective measures of students' meal plans were obtained from the university. Logistic generalized estimating equations (GEEs) were used to determine if students' meal plan, and meal plan use, predicted food insecurity. Linear GEEs were used to examine several potential reasons for lower meal plan use. We found that students did not use all of their available meals. Compared to students on the most expensive (unlimited) meal plan, students on the cheapest (8 meals/week) meal plan were the most likely to report food insecurity (OR = 2.2, 95% CI = 1.2, 4.1). However, in the Fall semester, 26% of students on unlimited meal plans also reported food insecurity. For students on the 180 meals/semester meal plan, food insecurity was associated with using fewer meals (OR = 0.9, 95% CI = 0.8, 1.0). Students who worked tended to use their meal plan less (β = -1.3, 95% CI = -2.3, -0.3). Students are reporting food insecurity while having meals left in their meal plan.

Background

There is ongoing debate about whether friends' greater similarity in Body Mass Index (BMI) than non-friends is due to friend selection, shared environments, or peer influence.

Methods

First-year college students (n = 104) from a southwestern U.S. university were randomly assigned roommates during the university's housing process, effectively removing friend selection effects. Participant BMI was measured up to four times (T1-T4) across 2015-2016. The influence of roommate baseline BMI (T1) on change in participant BMI over time (T2-T4) was analyzed using a linear mixed effects model adjusted for individual socio-demographics, linear time trends, baseline BMI, and physical clustering of students. A sensitivity analysis examining floormates was also conducted.

Results

Consistent with roommate influence, participants randomized to roommates with a higher BMI gained more weight between times T2 and T4 (β = 0.06; 95% CI = 0.02, 0.10). No shared environment effects (shared campus or floor) were found.

Conclusions

Randomly assigned roommates influenced each other's weight trajectories. This clarifies that BMI convergence can occur outside of friend selection or shared environments mechanisms.