Body composition changes during the first two years of university

Preventive Medicine 52 (2011) 20–22 Contents lists available at ScienceDirect Preventive Medicine j o u r n a l h o m e p a g e : w w w. e l s e v i e r. c o m / l o c a t e / y p m e d Body composition changes during the first two years of university Sareen S. Gropper a,⁎, Anna Newton a, Paul Harrington a, Karla P. Simmons b, Lenda Jo Connell b, Pamela Ulrich b a b Department of Nutrition, Dietetics, and Hospitality Management, 101 Poultry Science Bldg., Auburn University, AL 36849, USA Department of Consumer Affairs, 308 Spidle Hall, Auburn University, AL 36849, USA a r t i c l e i n f o Available online 8 November 2010 Keywords: Weight gain Body fat gain College students Sophomore year a b s t r a c t Objective. Changes in body weight, composition, and shape were investigated in male and female college students between the freshman and sophomore years. Methods. Changes in weight, body mass index (BMI), percent and absolute body fat and fat-free mass (via bioelectrical impedance), and waist circumference (via body scans) were assessed over the freshman and sophomore years (2007–2009) among 120 students attending a Southern public university. Results. Weight (2.5 and 1.7 lbs) and BMI gains (0.3 and 0.3 kg/m2) did not significantly differ between the freshman and sophomore years, respectively. Significantly more percent body fat and fat mass were gained during the freshman (1.9% and 3.3 lbs, respectively) than the sophomore year (0.0% and 0.6 lbs, respectively). Females lost significantly more fat-free mass during the freshman (−0.8 lb) than during the sophomore year (1.0 lb). Changes in waist circumference and weight were significantly correlated. Increases in the percentages of females classified as overweight and with unhealthy body fat amounts and waist circumferences were observed. Conclusion. While the sophomore year was characterized by slightly healthier body composition changes than the freshman year, the gains in weight, fat mass, and waist circumference measurements suggest increased health risks for many college females. © 2010 Elsevier Inc. All rights reserved. Introduction Weight gain among college students has been extensively studied during the freshman year; these studies report 4–5 lbs weight gains among first year students (Economos et al., 2008; Edmonds et al., 2008; Gropper et al., 2009; Hajhosseini et al., 2006; Hoffman et al., 2006; Holm-Denoma et al., 2008; Hovell et al., 1985; Jung et al., 2008; Levitsky et al., 2004; Mifsud et al., 2009; Provencher et al., 2009; Pullman et al., 2009). However, only a handful of studies have been conducted beyond this first year. During the sophomore year, weight gains of b2 lbs and increased overweight/obesity rates have been reported, but waist circumferences have not been studied and body composition has not been examined in both sexes (Hovell et al., 1985; Hull et al., 2007; Lloyd-Richardson et al., 2009; Racette et al., 2005). The purpose of the present study was to examine changes in weight, body mass index, percent and absolute fat mass and fat-free mass, and waist circumference in males and females during both their freshman and sophomore college years. ⁎ Corresponding author. Fax: +1 334 844 3268. E-mail address: [email protected] (S.S. Gropper). 0091-7435/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.ypmed.2010.10.008 Methods Participants Freshmen were recruited from a southern public university's incoming freshman class; a description of recruitment, the freshman class, and participant exclusion criteria are provided in Gropper et al. (2009). Informed consent was obtained prior to study participation. The study was approved by the university's Institutional Review Board for the Use of Human Subject in Research. Measures Participants were assessed at the beginning (first 4 weeks) of fall semester (2007, 2008, 2009). At assessments, height, weight, body composition, and waist circumference were measured and participants completed questionnaires that were part of a larger, longitudinal study. Bioelectrical impedance analysis was conducted using BodyStat (BioVant Systems, Detroit, MI), which has been validated for accuracy against several other body composition assessment methods (Benton and Swan, 2007; Fuller et al., 1994; Ghosh et al., 1997). Waist circumference was measured using 3-dimensional body scanning (TC2, Raleigh, NC). Body scans, using white light technology, obtain body measurements with a circumference accuracy of b 3 mm, a higher level than is achieved by traditional measurements (TC2, 2007). Participants were classified by BMI as underweight, normal weight, overweight, or obese (CDC, 2009). Further methodology information is provided in Gropper et al. (2009). 21 S.S. Gropper et al. / Preventive Medicine 52 (2011) 20–22 Statistical analyses Statistical analyses were performed using Instat 3.0 (GraphPad Software, San Diego, CA) and SPSS Statistics 17.0 (SPSS Inc., Chicago, IL). Ethnicity/race differences between the university freshman and study populations were examined using the Chi-squared test. Paired t-tests were used to compare differences in outcome measure changes and rate of weight change among participants for the freshman and sophomore years. Repeated-measures analysis of variance and Tukey's test were used to examine differences in outcome measures at the beginning and end of the freshman and sophomore years. A Student's t-test was used to compare the baseline weight and BMI of study returners versus non-returners. A Pearson's correlation was used to examine the relationship between weight and waist circumference changes. A p value of b 0.05 was considered statistically significant. Data are reported as mean (SD) unless noted differently. Results Study volunteers included 240 students (155 females, 85 males). Table 1 shows selected demographic and anthropometric information. Of the initial volunteers, 120 participants returned for all assessments and 150 participants (63%) returned for the last sophomore year assessment. Known non-returners included 24 participants (10%) who were no longer enrolled students and three females (1.2%) with reported eating disorders. The baseline weight and BMI of those who returned [145.7 (34.9) lbs and 23.0 (4.7) kg/m2, respectively] did not significantly differ from those of the non-returners [141.5 (26.7) lbs and 22.5 (3.5) kg/m2, respectively]. Absolute weight, BMI, percent body fat, fat mass, and waist circumference (but not fat-free mass) were significantly higher at the end of sophomore year than at the start of the freshman year (data not shown). Outcome measure changes are shown in Table 2. Females and males gained significantly more fat during the freshman versus sophomore year. Females also lost significantly more fat-free mass during the freshman versus the sophomore year. Fat-free mass change among the males approached significance (p = 0.092) with a freshman year loss and a sophomore year gain. Changes in waist circumference and weight were significantly (p b 0.0001) correlated for the freshman (r = 0.62) and sophomore (r = 0.72) years. Most participants (37%) gained weight both years. The rate of freshman year weight gain [0.21 (0.71) lb/month] did not significantly differ from the sophomore year [0.14 (0.55) lb/month]. Over the 2 years, 69% of participants gained weight [8.4 (7.3) lbs]. Percent body fat, fat mass, fat-free mass, and waist circumference gains among the weight gainers were 2.8% (2.9%), 6.1 (6.3) lbs, 2.2 (3.6) lbs, and 0.74 inch (1.62 inches), respectively. At the study's beginning and end, the percentages of participants classified as underweight (initially 5%, end 6%) and obese (initially 4%, end 5%) were similar. However, the percentages classified as overweight increased from 15% initially to 23% while those classified as normal weight decreased from 75% initially to 67% by the end of the sophomore year. Moreover, initially 13 females had N30% body fat and seven females had N35-inch waist circumference. By the study's end, 17 females had N30% body fat and 11 females had N35-inch waist circumference. Discussion This study's findings are important as prior studies have not investigated weight, body composition, and waist circumference changes in both males and females beyond the freshman year. Significantly greater fat gains were found for both males and females for the freshman versus the sophomore year. Females lost significantly more fat-free mass in the freshman versus sophomore year; males exhibited similar changes that approached statistical significance. These findings in males are new to the literature. The body composition findings in females are similar to those reported by Hull et al. (2007). Table 1 Selected demographic and anthropometric characteristics of the initial sample of 240 students attending a public university in the southern US, 2007–2009. Beginning of fall 2007 (n = 240) Gendera Male Female Age (years) Male Female Height (inches) Male Female Weight (pounds) Male Female Body mass index (kg/m2) Male Female Body fat (percent) Male Female Fat mass (pounds) Male Female Fat-free mass Male Female Waist circumference (inches) Male Female Racea Caucasian African American Hispanic Asian Other Permanent residencea Alabama Georgia Tennessee Texas North Carolina Florida Louisiana Arizona Maryland Illinois Mississippi Ohio Virginia Others (1 each from 22 different states) School Residencea Campus dorm Off campus apartment, house, duplex, or trailer With parents 85 (35) 155 (65) 18.2 (0.4) 18.1 (0.4) 70.0 (2.6) 64.7 (2.3) 163.5 (28.4) 133.5 (28.9) 23.5 (3.9) 22.4 (4.4) 11.0 (4.9) 22.6 (6.1) 18.6 (15.4) 31.6 (18.2) 143.0 (18.4) 101.8 (13.3) 32.28 (2.52) 29.80 (3.35) 196 29 7 4 4 (81.7) (12.1) (2.9) (1.7) (1.7) 149 37 11 9 7 4 2 2 2 2 2 2 2 9 (62.1) (15.4) (4.6) (3.8) (2.9) (1.7) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (0.4) (3.8) 147 (61.3) 90 (37.5) 2 (1.2) a Data are presented as n (percent) except for age, height, weight, body mass index, body fat percent, fat mass, fat-free mass, and waist circumference, which are expressed as mean (SD). Most (69%) participants (both sexes) gained weight, a finding similar to the 70% reported by Racette et al. (2005) but less than the 77% reported by Lloyd-Richardson et al. (2009). The absolute weight gains (4.2 lbs for all participants, 8.4 lbs for weight gainers) over the 2 years were fairly consistent with those (4 lbs overall gain, 9 lbs for weight gainers) of Racette et al. (2005) but slightly less than that (9 lbs overall gain) reported by Lloyd-Richardson et al. (2009). The decreased rate of weight gain between the freshman and sophomore years was also observed by Hovell et al. (1985) in female college students. Further, the observed BMI increases in males and females were like those reported by Racette et al. (2005), and the present study's rise in students classified as overweight was consistent with Lloyd-Richardson et al.'s (2009) findings. 22 S.S. Gropper et al. / Preventive Medicine 52 (2011) 20–22 Table 2 Body composition changes during the first 2 years of college among 150 students attending a public university in the southern US, 2007–2009. Changes Freshman Yeara Weight (lbs) All 2.5 Females 2.3 Males 2.8 BMI (kg/m2) All 0.3 Females 0.3 Males 0.3 Body fat (percent) All 1.9 Females 1.8 Males 2.2 FFM (percent) All −1.9 Females −1.8 Males −2.2 FFM (lbs) All −0.9 Females −0.8 Males −0.9 Fat mass (lbs) All 3.3 Females 3.1 Males 3.8 Waist (inches) All 0.02 Females −0.21 Males 0.50 Sophomore Yeara Two yearsb (8.7) (8.1) (9.9) 1.7 (6.7) 1.4 (7.1) 2.4 (5.7) 4.2 (9.3) 3.6 (9.5) 5.1 (8.8) (1.4) (1.3) (1.4) 0.3 (1.1) 0.2 (1.2) 0.3 (0.8) 0.6 (1.5) 0.5 (1.5) 0.7 (1.3) (3.0)* (3.2)* (2.7)* 0.0 (2.4)* −0.1 (2.6)* 0.3 (2.0)* 1.9 (3.1) 1.7 (3.3) 2.3 (2.7) (3.0)* (3.2)* (2.7)* 0.0 (2.4)* 0.1 (2.6)* −0.3 (2.0)* −1.9 (3.1) −1.7 (3.3) −2.3 (2.7) (5.0)* (4.5)* (6.1) 1.2 (3.9)* 1.0 (3.5)* 1.5 (4.7) 0.3 (5.1) 0.1 (4.9) 0.7 (5.5) (6.2)* (6.1)* (6.7)* 0.6 (4.9)* 0.4 (5.2)* 1.8 (4.2)* 3.9 (6.9) 3.5 (6.9) 5.3 (6.2) (1.54) (1.67) (1.23) 0.33 (1.26) 0.29 (1.36) 0.43 (1.05) 0.35 (1.59) 0.08 (1.71) 0.93 (1.12) *Values in rows are statistically significantly different p b 0.05. BMI = body mass index. FFM = fat-free mass. a n = 94 females, n = 46 males except waist circumference data where n = 73 females, n = 35 males. b n = 99 females, n = 51 males except waist circumference data where n = 88 females, n = 45 males. Yet, while BMI provides a good indicator of body fatness and mortality risk, health problems including cardiometabolic abnormalities are associated with abdominal obesity and with being “skinny fat” (e.g., normal BMI/high percentage of body fat) (Romero-Corral et al., 2008; Wildman et al., 2008). Waist circumference, an abdominal obesity indicator, is considered one of the best indicators of obesity-related health risks (Janssen et al., 2004). For every centimeter increment in waist circumference, cardiovascular risk increases by 2% (De Koning et al., 2007). In the present study, gains in weight, BMI, and fat mass were observed both years, and, by the study's end, more females had N30% body fat and N35-inch waist circumferences. Weight changes were also significantly correlated with waist circumference changes. These study findings, which are a unique addition to the published literature, suggest that the weight, fat, and waist circumference gains occurring during the first 2 years of college maybe increasing cardiovascular disease risks for some college females. Conclusion The freshman year is associated with weight gain and unhealthy body composition changes. While the sophomore year is characterized by slightly healthier body composition changes, fat mass, and weight gains occurred. The increased prevalence of females classified as overweight and with unhealthy body fat amounts and waist circumference measurements suggests increased health risks for many college females. Conflict of interest statement The authors declare that there are no conflicts of interest. None of the authors had any financial, personal, or other relationships with the organization sponsoring this research. 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