Increase in body mass index from normal weight to overweight in a cross-sectional sample of healthy research volunteers.

Current literature provides limited information about healthy volunteers serving as controls for biomedical research. This study describes trends in body mass index (BMI), a ratio of weight to height (kilograms per square meter), of the population of healthy volunteers at the National Institutes of Health Clinical Center (NIH CC) and compares these trends to a nationally representative sample, as reported by the National Health and Nutrition Examination Survey. We hypothesized that BMI trends at the NIH CC would follow those of the US population. This cross-sectional study examined the BMI of healthy volunteers at the NIH CC from 1976 to 1980, 1981 to 1987, 1988 to 1994, 1995 to 1998 and for all subsequent two-year periods onward until 2012. Study data were extracted from the NIH Biomedical Translational Research Information System. Subjects were selected based on a discharge code of "volunteer." Descriptive statistics of volunteers at the NIH CC were calculated for height, weight, age-adjusted BMI, age, and sex, and associations between categorical variables were analyzed using the χ2 test. Differences between BMI categories or periods for continuous independent variables were assessed using Kruskal-Wallis and post hoc Tamhane T2 tests. The 13 898 healthy volunteers with median age of 34 years were 53% female and primarily non-Hispanic whites. Mean BMI was within the normal category from 1976 to 1987. From 1988 on, mean BMI fluctuated but increased overall. The BMI of healthy volunteers at the NIH CC appears to follow national trends as described by National Health and Nutrition Examination Survey data of increasing body weight during the past three decades followed by a recent plateau.

The Massachusetts BMI letter: a qualitative study of responses from parents of obese children.

OBJECTIVES: Massachusetts (MA) public schools conduct mandated body-mass index (BMI) screening and until recently, communicated results in a letter to parents/caregivers, to encourage primary care visits and provide aggregate data to the state Department of Public Health. This study assessed the letter's readability and qualitatively explored parents' responses to it. METHODS: Readability of the BMI letter was calculated. Audio-taped 1-h focus groups were conducted with parents/caregivers of 8- to 14-year-old obese (≥95th BMI-for-age percentile) children. A semi-structured interview guide was used to elicit responses. Qualitative content analysis was conducted on transcripts to identify emergent themes. RESULTS: Readability analysis showed higher grade levels than recommended. Eight focus groups consisting of two to six parents each were conducted (n=29); 83% were female, mean age 41±9years, and 65% self-identified as Hispanic/Latino. Key themes identified included usefulness of the BMI letter, concerns about utility of BMI for screening, concerns about impacting self-esteem, and failure to understand the letter. CONCLUSIONS: The MA BMI letter may not have been achieving its desired goal with some parents. PRACTICE IMPLICATIONS: Emergent themes from this study could be used to test effectiveness of similar BMI letters nationwide and develop strategies to improve communication to parents.