Table 2.
The association between SP frequency and frailty based on fixed-effects model and time-varying Cox regression
| Fixed-effects model (n = 9422) | Time-varying Cox regression (n = 6073) | |||
|---|---|---|---|---|
| Coefficient (95%CI) | P value | HR(95%CI) | P value | |
| Frequency of SP (ref. Non SP) | ||||
| Occasional | 0.000 (-0.003, 0.002) | 0.776 | 0.93 (0.83, 1.04) | 0.187 |
| Weekly | -0.006 (-0.009, -0.003) | < 0.001 | 0.97 (0.86, 1.09) | 0.577 |
| Daily | -0.009 (-0.012, -0.007) | < 0.001 | 0.76 (0.69, 0.84) | < 0.001 |
| Age | 0.002 (0.001, 0.002) | < 0.001 | 1.01 (1.00, 1.01) | < 0.001 |
| Gender (ref. Male) | ||||
| Female | 0.019 (-0.043, 0.080) | 0.554 | 1.87 (1.67, 2.10) | < 0.001 |
| Rural/urban residence (ref. Rural) | ||||
| Urbana | – | – | 0.75 (0.68, 0.82) | < 0.001 |
| Education level (ref. Less than lower secondary) | ||||
| Upper secondary & vocational training | -0.014 (-0.025, -0.003) | 0.015 | 0.73 (0.64, 0.84) | < 0.001 |
| Tertiary | -0.025 (-0.046, -0.004) | 0.020 | 0.62 (0.42, 0.90) | 0.013 |
| Marital status (ref. Divorced or widowed) | ||||
| Married | -0.027 (-0.032, -0.021) | < 0.001 | 0.77 (0.68, 0.86) | < 0.0001 |
| Hukou status (ref. Agricultural) | ||||
| Non-agricultural | -0.010 (-0.016, -0.004) | 0.002 | 0.74 (0.66, 0.84) | < 0.001 |
| Other | -0.010 (-0.019, 0.000) | 0.044 | 0.81 (0.56, 1.18) | 0.274 |
| Public health insurance coverage (ref. Not covered) | ||||
| Covered | 0.002 (-0.002, 0.006) | 0.441 | 0.83 (0.69, 1.00) | 0.045 |
| Current work status (ref. Not working) | ||||
| Working | -0.018 (-0.020, -0.015) | < 0.001 | 0.94 (0.86, 1.03) | 0.194 |
| Comorbidity (ref. None) | ||||
| Single | 0.030 (0.026, 0.034) | < 0.001 | 2.10 (1.83, 2.41) | < 0.001 |
| Morbidity | 0.072 (0.067, 0.076) | < 0.001 | 5.03 (4.43, 5.70) | < 0.001 |
| Household per capita consumption group (ref. low) | ||||
| Low to middle | 0.000 (-0.003, 0.002) | 0.890 | 0.91 (0.81, 1.02) | 0.089 |
| Middle | 0.008 (0.005, 0.010) | < 0.001 | 0.93 (0.84, 1.04) | 0.232 |
| High | 0.014 (0.011, 0.016) | < 0.001 | 0.97 (0.87, 1.09) | 0.612 |
| Alcohol intake (ref. Do not drink) | ||||
| Drink | -0.001 (-0.004, 0.002) | 0.407 | 0.96 (0.88, 1.06) | 0.434 |
| Smoking status (ref. Never) | ||||
| Quit now | 0.011 (0.006, 0.016) | < 0.001 | 1.20 (1.05, 1.38) | 0.008 |
| Smoke now | 0.000 (-0.005, 0.005) | 0.973 | 1.25 (1.11, 1.40) | < 0.001 |
HR Hazard ratio, CI Confidence Interval
aThe variable “Rural/urban residence” was omitted in the fixed-effects model because of collinearity