title: Food Insecurity and Body Mass Index: A Longitudinal Mixed Methods Study, Chelsea, Massachusetts, 2009-2013.
abstract: BACKGROUND
  Cross-sectional studies show an association between food insecurity and higher body mass index (BMI), but this finding has not been evaluated longitudinally. Patient perspectives on food choice in resource-constrained environments are not well understood. The objective of this study was to evaluate the longitudinal association between food insecurity and BMI.
  
  
  METHODS
  This mixed methods study used both a retrospective matched cohort and focus groups. For the quantitative analysis, all patients in a community health center who reported food insecurity from October 2009 through March 2010 (n = 457) were followed through August 2013 and compared with controls matched by age, sex, and race/ethnicity (n = 1,974). We evaluated the association between food insecurity and change in BMI by using linear, mixed effects longitudinal models. The qualitative analysis included patients with food insecurity, stratified by BMI. Qualitative data were analyzed by using open coding and grounded theory.
  
  
  RESULTS
  The mean age of participants was 51 years; 61% were women, and 73% were Hispanic. Baseline BMI was similar in food insecure participants and matched controls. After adjustment in longitudinal analyses, food insecurity was associated with greater increase in BMI (0.15 kg/m(2) per year more than controls, P < .001). Themes identified in 4 focus groups included attitudes and knowledge about food, food access, and food practices. Participants with BMI of 30 kg/m(2) or less highlighted skills such as budgeting and portion control.
  
  
  CONCLUSIONS
  Food insecurity is associated with increase in BMI. The skills of food insecure participants who were not obese, such as portion control and budgeting, may be useful in weight management interventions for vulnerable patients.
authors.affiliation: Adult Medicine, Chelsea Health Care Center, 151 Everett Ave, Chelsea, MA 02150.Email: Chencheung.hong@mgh.harvard.edu. Dr Chen is also affiliated with the Harvard Medical School, Boston, Massachusetts.
authors.forename: Hong Chen
authors.initials: HC
authors.lastname: Cheung
authors.affiliation: Injury Prevention at Boston Public Health Commission, Boston, Massachusetts.
authors.forename: Aileen
authors.initials: A
authors.lastname: Shen
authors.affiliation: Community Health Department, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Sarah
authors.initials: S
authors.lastname: Oo
authors.affiliation: Department of Internal Medicine, Beth Israel Deaconess Hospital, Boston, Massachusetts.
authors.forename: Hailu
authors.initials: H
authors.lastname: Tilahun
authors.affiliation: Adult Medicine, Massachusetts General Hospital, Chelsea Health Care Center, Chelsea, Massachusetts, Harvard Medical School, Boston, Massachusetts, Division of General Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Marya J
authors.initials: MJ
authors.lastname: Cohen
authors.affiliation: Harvard Medical School, Boston, Massachusetts, Division of General Internal Medicine, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Seth A
authors.initials: SA
authors.lastname: Berkowitz
mesh_terms: D015992:Body Mass Index; D016022:Case-Control Studies; D002755:Choice Behavior; D003430:Cross-Sectional Studies; D004779:Environment Design / Q000639:trends; D005260:Female; D017144:Focus Groups; D005523:Food Supply / Q000191:economics / Q000592:standards / Q000706:statistics & numerical data*; D066296:Grounded Theory; D007722:Health Knowledge, Attitudes, Practice / Q000208:ethnology; D054624:Health Status Disparities; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology / Q000517:prevention & control*; D017063:Outcome Assessment, Health Care; D036301:Qualitative Research; D014186:Transportation