Table 4.
Negative binomial regression on predicting smoking intensity with age at smoking initiation at Step 1 and after controlling for potential confounders at Step 2, based on the 2021 GATS, a cross-sectional survey (N=2260)*
| Parameter | β | SE | 95% CI | p | |
|---|---|---|---|---|---|
| Lower | Upper | ||||
| Unadjusted for other variables | |||||
| Age at smoking initiation | -0.0144 | 0.0023 | -0.0189 | -0.0099 | <0.0001 |
| After adjusting for other variables | |||||
| Age at smoking initiation | -0.0156 | 0.0024 | -0.0204 | -0.0108 | <0.0001 |
| Sex (female) | -0.1146 | 0.0516 | -0.2157 | -0.0136 | 0.0262 |
| Age (years) | 0.0072 | 0.0011 | 0.0050 | 0.0094 | <0.0001 |
| Education level (higher than elementary level) | 0.0189 | 0.0341 | -0.0480 | 0.0857 | 0.5802 |
| Employment (employed) | 0.0683 | 0.0447 | -0.0193 | 0.1559 | 0.1267 |
| Income (>4999 PHP) | 0.0414 | 0.0325 | -0.0223 | 0.1051 | 0.2024 |
| Believes that tobacco smoking can cause serious illness (no) | -0.0064 | 0.0575 | -0.1191 | 0.1063 | 0.9111 |
| Smoking rules at home (smoking allowed) | 0.1807 | 0.0322 | 0.1175 | 0.2439 | <0.0001 |
Step 1: Smoking intensity was regressed on age at smoking initiation. Step 2: Smoking intensity was regressed on age at smoking initiation while controlling for other variables. Reference values of categorical predictors: males; elementary education and below; not employed; ≤4999 PHP; yes; smoking not allowed/no rules.
*
After eliminating cases with missing, refused, and don’t know responses. PHP: 1000 Philippine Pesos about US$17.