Table 3. Overall and Subgroup Results by the Differences-in-Difference Analysisa.
| Characteristic | Additive differences in mean BMI (95% CI)b | Percentage point change in adults with overweight or obesity (95% CI) |
|---|---|---|
| Overall | −0.132 (−0.277 to 0.014) | 0.4 (−1.2 to 2.0) |
| City | ||
| Albany | −0.012 (−0.275 to 0.251) | −0.5 (−4.6 to 3.7) |
| Berkeley | −0.156 (−0.268 to −0.043)c | −0.1 (−1.8 to 1.6) |
| Oakland | −0.100 (−0.200 to 0.001) | 0.8 (−1.0 to 2.5) |
| San Francisco | −0.152 (−0.327 to 0.023) | 0.3 (−1.1 to 1.7) |
| Age, y | ||
| 20-25 | −0.295 (−0.513 to −0.077)c | −1.0 (−3.7 to 1.7) |
| 26-39 | −0.194 (−0.369 to −0.020)c | 0.6 (−1.5 to 2.8) |
| 40-54 | −0.110 (−0.242 to 0.022) | 0.5 (−1.0 to 1.9) |
| 55-65 | −0.045 (−0.172 to 0.083) | 0.3 (−1.3 to 1.9) |
| Sex | ||
| Female | −0.185 (−0.261 to −0.109)c | −0.1 (−1.6 to 1.5) |
| Male | −0.065 (−0.136 to 0.007) | 1.1 (−0.6 to 2.7) |
| Race and ethnicity | ||
| Asian or Pacific Islander | −0.133 (−0.278 to 0.012) | 0.4 (−1.7 to 2.5) |
| Black | −0.094 (−0.206 to 0.019) | −0.3 (−1.6 to 1.0) |
| Hispanic | −0.054 (−0.223 to 0.115) | 0.2 (−1.7 to 2.0) |
| White | −0.193 (−0.345 to −0.040)c | 0.7 (−0.5 to 1.9) |
| Otherd | −0.006 (−0.115 to 0.103) | 0.7 (−1.5 to 2.8) |
| High poverty cohorte | −0.018 (−0.152 to 0.117) | 1.5 (0.5 to 2.4)c |
| Posttax implementation year | ||
| 1 (tax implementation)f | −0.098 (−0.282 to 0.086) | 0.3 (−1.8 to 2.4) |
| 2 | −0.123 (−0.318 to 0.072) | 0.5 (−1.7 to 2.7) |
| 3 | −0.156 (−0.363 to 0.051) | 0.3 (−2.1 to 2.6) |
| 4 | −0.142 (−0.452 to 0.168) | 0.7 (−2.6 to 3.9) |
| 5g | −0.235 (−0.442 to −0.029)c | −0.7 (−3.8 to 2.4) |
| 6g | −0.217 (−0.515 to 0.082) | −0.7 (−5.3 to 3.9) |
Abbreviation: BMI, body mass index.
a
Estimates are jointly controlled for race and ethnicity, age, gender, insurance status, and city by year fixed effects, as well as intraclass correlation within patients.
b
Calculated as weight in kilograms divided by height in meters squared.
c
P value ≤.05.
d
Other race refers to American Indian or Alaskan Native, multiracial, and other races and ethnicities not listed or unknown.
e
Refers to primary residence with neighborhood household poverty greater than 20% based on US Census data.
f
Year of tax implementation is 2015 in Berkeley and 2017 for Albany, San Francisco, and Oakland.
g
Berkeley had 2 additional years of data. Estimates presented are calculated for Berkeley only.