Table 2. Unadjusted and Adjusteda Longitudinal Results for Change in Body Mass Index (BMI) and Weight Over Time, by Food Security Status, Chelsea, Massachusetts, 2009–2013.
| Variable | Unadjusted BMI, kg/m2
|
Unadjusted Weight, kg |
Adjusteda BMI, kg/m2
|
Adjusteda Weight, kg |
||||
|---|---|---|---|---|---|---|---|---|
| Estimate (95% CI) | P Value | Estimate (95% CI) | P Value | Estimate (95% CI) | P Value | Estimate (95% CI) | P Value | |
| Difference at baseline for food | 0.39 (−0.35 to 1.14) | .30 | 1.17 (−0.69 to 3.03) | .22 | 0.20 (−0.61 to 1.01) | .63 | 0.69 (−1.18 to 2.55) | .47 |
| Food secure | 1 [Reference] | |||||||
| Change per yearb (overall) | −0.12 (−0.14 to −0.09) | <.001 | 20.0 (−0.25 to −0.14 | <.001 | −0.13 (−0.16 to −0.10) | <.001 | −0.22 (−0.28 to −0.16) | <.001 |
| Differential change per year among food insecure participantsb | 0.15 (0.10 to 0.20) | <.001 | 0.33 (0.22 to 0.44) | <.001 | 0.15 (0.10 to 0.20) | <.001 | 0.31 (0.19 to 0.43) | <.001 |
| Differential change among food secure controls | 1 [Reference] | |||||||
| Age (years) | — | — | — | — | 0.47 (0.32 to 0.62) | <.001 | 1.21 (0.88 to 1.55) | <.001 |
| Agea × age (years2) | — | — | — | — | −0.0004 (−0.006 to −0.003) | <.001 | −0.01 (−0.02 to −0.01) | <.001 |
| Sex | ||||||||
| Female | — | — | — | — | 0.36 (−0.36 to 1.07) | .33 | −11.3 (−12.8 to −9.7) | <.001 |
| Male | 1 [Reference] | |||||||
| Race/ethnicity | ||||||||
| Non-Hispanic black | — | — | — | — | 0.29 (−1.37 to 1.85) | .77 | 2.65 (−1.01 to 6.31) | .16 |
| Hispanic | — | — | — | — | −0.22 (−1.36 to 0.91) | .70 | −4.15 (−6.66 to −1.65) | .001 |
| Asian/other | — | — | — | — | −0.90 (−2.99 to 1.18) | .39 | −7.65 (−12.22 to −3.08) | .001 |
| Non-Hispanic white | 1 [Reference] | |||||||
| Insurance | ||||||||
| Medicare | — | — | — | — | 0.87 (−0.20 to 1.95) | .11 | 2.74 (0.32 to 5.16) | .03 |
| Medicaid | — | — | — | — | 0.45 (−0.37 to 1.27) | .28 | 1.58 (−0.22 to 3.39) | .09 |
| None/Self-pay | — | — | — | — | −0.14 (−1.96 to 1.68) | .88 | 0.05 (−3.69 to 3.79) | .98 |
| Commercial | 1 [Reference] | |||||||
| Education level | ||||||||
| <High school diploma | — | — | — | — | 0.74 (−0.02 to 1.50) | .06 | 0.04 (−1.61 to 1.69) | — |
| High school diploma | 1 [Reference] | |||||||
| Census block group median household income (dollars) | — | — | — | — | −0.00002 (−0.00004 to 0.000009) | .20 | −0.00001 (−0.00007 to 0.00004) | .61 |
| English as primary language | — | — | — | — | −0.72 (−1.66 to 0.23) | .14 | −3.82 (−5.87 to −1.77) | <.001 |
Abbreviations: —, matching variable; CI, confidence interval.
a
Adjusted for all variables in table.
b
Because of the presence of a differential change by food security status (interaction) term in the regression models, to determine the change in BMI or weight per year for food insecure participants, the overall change in BMI (or weight) term was added to the differential change term. For food secure participants, only the overall term was used (because food secure participants are the reference group, their interaction term coefficient is 0). Thus, the models estimate that BMI and weight will decrease for food secure participants over time but will increase or stay the same for food insecure participants.