Table 4.
Decomposition of risk factors: the nine SQMSQ itemsa, b, c, d
| Cognitive functioning: No. of incorrect answers [t=baseline] |
Cognitive decline: Increase in the no. of incorrect answers [t+ 1]-[t] |
Cognitive impairment | ||||
|---|---|---|---|---|---|---|
| Male | 0.622 (0.024) | 0.577 (0.025) | 1.104 (1.088–1.121) | |||
| Women | 0.857 (0.023) | 0.581 (0.022) | 1.137 (1.121–1.153) | |||
| Difference | − 0.235**(0.033) | − 0.004 (0.033) | 0.971**(0.952–0.991) | |||
| Explained | Unexplained | Explained | Unexplained | Explained | Unexplained | |
| Overall | −0.116**(0.036) | −0.119*(0.046) | − 0.124**(0.035) | 0.121**(0.047) | 0.949**(0.922–0.976) | 1.024 (0.987–1.062) |
| Age | 0.046 (0.038) | 2.975 (7.742) | 0.047 (0.041) | −15.775*(7.764) | 1.002 (0.981–1.024) | 0.034 (0.000–3.964) |
| Age2/100 | − 0.057 (0.040) | −1.422 (3.791) | − 0.063 (0.043) | 7.618*(3.754) | 0.993 (0.972–1.015) | 4.729 (0.500–44.693) |
| Years of education | − 0.153**(0.037) | 2.287**(0.615) | −0.118**(0.036) | − 0.577 (0.713) | 0.964**(0.944–0.983) | 1.093 (0.775–1.542) |
| Years of education2/100 | 0.101**(0.036) | − 0.974**(0.306) | 0.094**(0.035) | 0.234 (0.336) | 1.022*(1.001–1.045) | 0.933 (0.771–1.130) |
| Current worker | − 0.024**(0.008) | 0.015 (0.025) | 0.002 (0.009) | 0.006 (0.028) | 0.996 (0.990–1.002) | 1.009 (0.989–1.029) |
| Longest occupation (Ref. Professional) | ||||||
| Clerical | − 0.005 (0.006) | 0.010 (0.027) | − 0.005 (0.006) | − 0.018 (0.026) | 0.999 (0.994–1.004) | 0.979 (0.951–1.008) |
| Manual | 0.018 (0.013) | −0.009 (0.029) | 0.022#(0.013) | 0.029 (0.028) | 1.007 (0.996–1.019) | 0.986 (0.960–1.012) |
| Agriculture/forestry/fishery | 0.011*(0.005) | 0.002 (0.019) | 0.003 (0.005) | −0.024 (0.019) | 1.003 (0.999–1.007) | 0.987 (0.971–1.003) |
| Domestic worker | −0.019 (0.025) | − 0.008 (0.031) | −0.059*(0.025) | − 0.007 (0.029) | 0.979*(0.959–0.999) | 0.981 (0.946–1.016) |
| Single | −0.042**(0.015) | 0.026 (0.020) | −0.008 (0.015) | − 0.022 (0.017) | 0.991 (0.981–1.002) | 0.993 (0.980–1.006) |
| Home ownership | −0.001 (0.002) | − 0.076 (0.085) | −0.002 (0.002) | − 0.052 (0.096) | 0.999 (0.998–1.001) | 0.964 (0.902–1.030) |
| Group activity | −0.001 (0.002) | − 0.045 (0.044) | −0.005*(0.002) | − 0.011 (0.049) | 0.999#(0.997–1.000) | 0.972 (0.937–1.008) |
| Current smoker | 0.003 (0.015) | −0.006 (0.016) | − 0.008 (0.017) | −0.010 (0.017) | 0.999 (0.987–1.010) | 0.996 (0.984–1.008) |
| Alcohol consumption | 0.017 (0.015) | −0.011 (0.030) | − 0.035*(0.016) | 0.015 (0.032) | 0.993 (0.982–1.004) | 0.999 (0.978–1.021) |
| Exercise | −0.004#(0.002) | − 0.018 (0.031) | −0.001 (0.002) | − 0.023 (0.034) | 0.999 (0.998–1.000) | 1.002 (0.980–1.025) |
| Hearing impairment | 0.002 (0.002) | 0.000 (0.008) | 0.001 (0.002) | − 0.019*(0.009) | 1.001 (1.000–1.002) | 0.998 (0.994–1.002) |
| Diabetes | −0.001 (0.002) | 0.012 (0.008) | −0.002 (0.003) | − 0.005 (0.010) | 1.000 (0.999–1.002) | 1.002 (0.995–1.008) |
| Hypertension | 0.005*(0.002) | 0.009 (0.019) | 0.000 (0.002) | 0.004 (0.021) | 1.000 (0.999–1.002) | 0.996 (0.982–1.010) |
| Stroke | −0.000 (0.001) | − 0.008 (0.008) | 0.001 (0.002) | 0.007 (0.008) | 1.000 (1.000–1.001) | 0.999 (0.994–1.004) |
| Constant | −2.753 (3.980) | 8.740*(4.059) | 7.189 (0.550–94.038) | |||
| Observations | 3581 | |||||
a Coefficients with robust standard errors in parentheses estimated by the linear model for ‘cognitive functioning’ and ‘cognitive decline’; Odds ratios with 95% confidence intervals based on robust standard errors in parentheses estimated by the logit model for ‘Cognitive impairment’. ** p< 0.01, * p< 0.05, # p< 0.10
b Participating waves are included in the models
c Cognitive impairment: Three or more incorrect answers out of nine
d Analyses were conducted by STATA command ‘oaxaca’ [46]