Table 1.
Time-Varying Characteristics of Participants in a Study of Neighborhood Food Environment and Adult Body Mass Index, Northern California, 2006–2011
| Variable | Mean | Standard Deviation | Minimum | Maximum | No. of Individuals | No. of Observations | ||
|---|---|---|---|---|---|---|---|---|
| Overall | Between-Person | Within-Person | ||||||
| BMIa | 31.83 | 7.26 | 7.04 | 1.69 | 15 | 134 | 214,830 | 2,815,549 |
| Good food environment (kernel density) | 0.34 | 0.46 | 0.45 | 0.01 | 0 | 5.7 | 198,030 | 2,810,220 |
| Age, years | 63.43 | 13.07 | 13.23 | 1.47 | 18 | 109 | 214,826 | 3,212,896 |
| Medicaid enrollment (yes/no) | 0.02 | 0.15 | 0.12 | 0.04 | 0 | 1 | 213,113 | 3,003,353 |
| CCI scoreb | 2.17 | 1.92 | 1.45 | 0.99 | 0 | 19 | 214,830 | 3,212,923 |
| Insulin use (yes/no) | 0.20 | 0.40 | 0.32 | 0.18 | 0 | 1 | 214,830 | 3,212,923 |
| Oral medication use (yes/no) | 0.42 | 0.49 | 0.42 | 0.25 | 0 | 1 | 214,830 | 3,212,923 |
| Medication causing weight gain (yes/no) | 0.07 | 0.25 | 0.18 | 0.14 | 0 | 1 | 214,830 | 3,212,923 |
| Medication causing weight loss (yes/no) | 0.09 | 0.28 | 0.21 | 0.15 | 0 | 1 | 214,830 | 3,212,923 |
| Quality of BMI measurement | 0.97 | 0.18 | 0.11 | 0.16 | 0 | 1 | 214,830 | 2,815,549 |
| Month of BMI measurement | 6.41 | 3.40 | 1.54 | 3.23 | 0 | 1 | 214,830 | 2,815,549 |
| Census block group characteristicsc | ||||||||
| Population density, persons/square miled | 8,118.38 | 8,705.75 | 8,588.29 | 1,976.85 | 0 | 227,475 | 198,206 | 2,295,612 |
| Proportion white | 0.59 | 0.23 | 0.23 | 0.05 | 0 | 1 | 198,206 | 2,295,612 |
| Proportion black | 0.08 | 0.11 | 0.11 | 0.03 | 0 | 1 | 198,206 | 2,295,612 |
| Proportion below federal poverty line | 0.11 | 0.11 | 0.10 | 0.03 | 0 | 1 | 198,206 | 2,295,612 |
Abbreviations: BMI, body mass index; CCI, Charlson comorbidity index.
a Weight (kg)/height (m)2.
b The possible range of scores in the CCI (27) is 0–33. The range in this data set was 0–19.
c Measured at the US Census block group level.
d Number of persons per square mile (per 1.6 km2).