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. 2015 May 13;100(6):F486–F491. doi: 10.1136/archdischild-2014-307265

Table 2.

Relative risks of late and moderately preterm (LMPT) birth for lifestyle factors from multivariable model, before and after including mother's age, ethnicity, body mass index (BMI) and educational level

Indicator Risk of late and moderate preterm birth
Model including lifestyle factors Model including lifestyle factors adjusted for socio-demographic factors
Relative risk 95% CI p Value Relative risk 95% CI p Value
Lifestyle factors
Use of recreational drugs during pregnancy
 No 1 0.486 1 0.495
 Yes 1.27 0.65 to 2.51 1.27 0.64 to 2.50
Smoking status
 Non-smoker 1 0.027 1 0.082
 Gave up before pregnancy 0.86 0.67 to 1.09 0.93 0.72 to 1.20
 Gave up in first trimester 1.07 0.73 to 1.56 1.12 0.76 to 1.66
 Smoker during pregnancy 1.35 1.05 to 1.72 1.38 1.04 to 1.84
Alcohol use
 Non-drinker 1 0.205 1 0.918
 Gave up before pregnancy 0.83 0.66 to 1.04 1.02 0.78 to 1.34
 Gave up in first trimester 0.78 0.61 to 0.99 0.98 0.73 to 1.31
 Drank during pregnancy 0.86 0.66 to 1.13 1.08 0.79 to 1.48
Daily consumption of five fruit and vegetables
 At least once a week 1 0.022 1 0.027
 Never 1.31 1.04 to 1.64 1.31 1.03 to 1.66
Mediterranean diet factors
 ≥1 1 0.052 1 0.036
 None 1.71 1.00 to 2.92 1.81 1.04 to 3.14
Socio-demographic factors
Mother's age (years)
 <20 1 0.585
 20–29 1.31 0.86 to 1.99
 30–39 1.37 0.88 to 2.13
 40+ 1.32 0.71 to 2.45
Mother's educational level
 Degree level and above 1 0.052
 University-access level 1.29 1.00 to 1.66
 Upper secondary qualification 1.36 1.06 to 1.76
 No formal/lower secondary qualification 1.42 1.06 to 1.89
Mother's ethnicity
 White 1 0.025
 Mixed 1.70 0.97 to 2.99
 Asian or Asian British 1.54 1.13 to 2.11
 Black or Black British 1.36 0.89 to 2.08
 Chinese or other ethnic group 1.99 0.87 to 4.55
Mother's BMI
 20.0–24.9 1 0.001
 <20 1.12 0.75 to 1.67
 25.0–29.9 0.80 0.64 to 1.00
 ≥30 0.58 0.45 to 0.76
 No pre-pregnancy weight recorded 1.07 0.57 to 2.02