Table 2.
Random effect estimates of factors influencing BMI from a specification using discrete variables to indicate birth cohort differences and their interactions with genetic factors
| Explanatory variables | Random effects estimates |
| Subject is male | 1.641*** (0.146) |
| Age 30–34.99 | 0.477*** (0.174) |
| Age 35–39.99 | 0.608*** (0.174) |
| Age 40–44.99 | 1.011*** (0.188) |
| Age 45–49.99 | 1.199*** (0.212) |
| Age 50–54.99 | 1.231*** (0.238) |
| Age 55–59.99 | 1.272*** (0.269) |
| Age 60–63 | 1.229*** (0.300) |
| Subject was born after 1942 | −1.360*** (0.280) |
| AA genotype | 0.708* (0.398) |
| AT genotype | −0.412 (0.282) |
| Born after 1942 by AA genotype | 1.041** (0.459) |
| Born after 1942 by AT genotype | 1.135*** (0.326) |
| Constant | 24.01*** (0.250) |
| Observations | 19,617 |
| R2 | 0.106 |
| No. of individuals | 3,720 |
Presented are the estimates of the age–period–cohort model where the cohort variable is treated as discrete. Each entry refers to the effect of the variable listed in the first column on BMI holding all other factors constant. SEs are presented in parentheses. Specifications also include gene-by-age (g-by-a) interactions and the estimates of all other factors included in this model as well as other estimators are presented in Table S2. See Table S6 for the calendar time corresponding to examinations in each wave. Note that our main results of birth cohort and genotype interactions are not sensitive to the method by which the model was estimated. The following indicate statistical significance of each explanatory variable: ***P < 0.01, **P < 0.05, and *P < 0.1.