Table 2 Parameter estimates for preterm birth (n = 15,593) associated with individual and area level characteristics among all singleton births (n = 330,688) during 2005-2010 in Finland
Characteristics | Model 1 adjusted for year of birth | Model 2 adjusted for individual level confounders | Model 3 adjusted for municipality level confounders | Model 4 adjusted for model 2 (except smoking) and Model 3 | Model 5 adjusted for model 2 and model 3 |
|---|---|---|---|---|---|
OR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | aOR (95% CI) | |
Year of birth | 0.99 (0.99-1.00) | 0.99 (0.98-1.00) | 0.99 (0.98-1.00) | 0.99 (0.98-1.00) | |
Maternal age, years (per one year increase) | 1.02 (1.02-1.03) | 1.02 (1.02-1.02) | 1.02 (1.02-1.03) | ||
Parity | |||||
Nulliparous women | 1 | 1 | 1 | ||
Multiparous women | 0.52 (0.50-0.54) | 0.52 (0.50-0.54) | 0.51 (0.49-0.53) | ||
Prior preterm birth | 5.28 (5.00-5.57) | 5.30 (5.03-5.59) | 5.27 (4.99-5.56) | ||
Smoking status | |||||
Non-smoking | 1 | 1 | |||
Quit smoking during 1st trimester | 1.03 (0.95-1.12) | 1.03 (0.95-1.11) | |||
Smoking after 1st trimester | 1.36 (1.29-1.43) | 1.35 (1.29-1.42) | |||
Missing information | 2.05 (1.89-2.22) | 2.02 (1.86-2.19) | |||
Socioeconomic status | |||||
Upper white collar workers | 1 | 1 | 1 | ||
Lower white collar workers | 1.15 (1.07-1.23) | 1.15 (1.07-1.23) | 1.13 (1.06-1.21) | ||
Blue collar workers | 1.19 (1.11-1.29) | 1.23 (1.14-1.33) | 1.18 (1.09-1.27) | ||
Othersa | 1.11 (1.03-1.19) | 1.12 (1.05-1.20) | 1.10 (1.03-1.18) | ||
Missing information | 1.27 (1.14-1.32) | 1.27 (1.18-1.36) | 1.24 (1.15-1.33) | ||
Municipality derivation class b | |||||
Education | |||||
High (least deprived) | 1 | 1 | 1 | ||
Intermediate | 1.05 (1.00-1.10) | 1.06 (1.01-1.11) | 1.06 (1.01-1.11) | ||
Low (most deprived) | 1.03 (0.97-1.10) | 1.03 (0.97-1.10) | 1.03 (0.96-1.10) | ||
Income | |||||
High (least deprived) | 1 | 1 | 1 | ||
Intermediate | 1.03 (0.98-1.09) | 1.05 (0.99-1.11) | 1.05 (0.99-1.11) | ||
Low (most deprived) | 1.05 (0.98-1.12) | 1.07 (1.00-1.14) | 1.06 (0.99-1.14) | ||
Unemployment | |||||
Low (least deprived) | 1 | 1 | 1 | ||
Intermediate | 1.02 (0.98-1.07) | 1.03 (0.98-1.08) | 1.02 (0.98-1.08) | ||
High (most deprived) | 1.04 (0.99-1.10) | 1.05 (1.00-1.11) | 1.05 (0.99-1.11) | ||
Log (population) | 1.01 (0.99-1.02) | 1.00 (0.98-1.01) | 1.00 (0.98-1.02) |