Table 4.
Adjusted longitudinal mixed models exploring the main effect of polygenic score for BMI (BMI-PGS) and income, and interactions between these two variables in relation to BMI trajectories during the 12-year follow-up period.
| < 65 Years of age | > 65 Years of age | |||||||
|---|---|---|---|---|---|---|---|---|
| Men | Women | Men | Women | |||||
| β | 95% CI | β | 95% CI | β | 95% CI | β | 95% CI | |
| Baseline | ||||||||
| PGS | 1.41*** | 1.12 to 1.69*** | 1.52*** | 1.17–1.85*** | 0.85*** | 0.47–1.22*** | 1.33*** | 0.75–1.91*** |
| High income | – | – | – | – | – | – | – | – |
| Intermediate income | 0.09 | − 0.36 to 0.56 | 0.51 | − 0.04 to 1.06 | − 0.67* | − 1.21 to − 0.13* | 0.81* | 0.09–1.53* |
| Low income | − 0.39 | − 0.91 to 0.13 | 0.55 | − 0.02 to 1.13 | − 0.35 | − 0.87 to 0.18 | 0.86* | 0.18–1.48* |
| PGS × high income | – | – | – | – | – | – | – | – |
| PGS × intermediate income | 0.17 | − 0.29 to 0.63 | 0.14 | − 0.41 to 0.69 | − 0.09 | − 0.61 to 0.43 | − 0.24 | − 1.01 to 0.51 |
| PGS × Low income | − 0.72** | − 1.21 to − 0.23** | − 0.22 | − 0.78 to 0.33 | 0.22 | − 0.28 to 0.73 | − 0.17 | − 0.84 to 0.50 |
| Rate of change | ||||||||
| PGS | − 0.00 | − 0.02 to 0.02 | 0.01 | − 0.01 to 0.04 | 0.01 | − 0.02 to 0.05 | − 0.02 | − 0.09 to 0.06 |
| High income | – | – | – | – | – | – | – | – |
| Intermediate income | 0.03 | − 0.01 to 0.08 | 0.03 | − 0.02 to 0.07 | 0.05 | − 0.01 to 0.12 | − 0.03 | − 0.08 to 0.08 |
| Low income | 0.03 | − 0.02 to 0.08 | 0.03 | − 0.01 to .08 | 0.06 | − 0.00 to 0.12 | − 0.04 | − 0.12 to 0.04 |
| PGS × high income | – | – | – | – | – | – | – | – |
| PGS × intermediate income | 0.00 | − 0.04 to 0.04 | − 0.04 | − 0.08 to 0.01 | 0.01 | − 0.06 to 0.07 | 0.06 | − 0.03 to 0.15 |
| PGS × low income | 0.01 | − 0.03 to 0.06 | 0.02 | − 0.02 to 0.08 | − 0.03 | − 0.09 to 0.03 | 0.04 | − 0.05 to 0.13 |
| Variancea | ||||||||
| Within-person | 0.04 | 0.03–0.05 | 0.05 | 0.04–0.06 | 0.03 | 0.02–0.07 | 0.04 | 0.02–0.08 |
| In initial status | 16.02 | 14.88–17.25 | 25.22 | 23.57–26.99 | 13.59 | 11.33–14.67 | 20.95 | 18.95–23.16 |
| In rate of change | 0.06 | − 0.02 to .14 | − 0.04 | − 0.15 to 0.07 | 0.07 | − 0.02 to 0.15 | − 0.02 | − 0.12 to 0.08 |
The adjusted models were adjusted for 4 principal components to account for any ancestry differences in genetic structures that could bias the results, as well as; marital status, physical activity level, presence of longstanding limiting illness, self-reported health, depressive symptoms, and smoking status.
CI, confidence intervals; PGS, polygenic score; BMI, body mass index.
aThe within-person variance is the overall residual variance in cognition that is not explained by the model. The initial status variance component is the variance of individuals’ intercepts about the intercept of the average person. The rate of change variance component is the variance of individual slopes about the slope of the average person.
×Represents an interaction between the two factors; interactions are presented based on multiplicative interaction model.
***p ≤ 0.001, **p ≤ 0.01, *p ≤ 0.05.