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Table 3 Maternal characteristics determining membership in a particular group, relative to Group 1

From: Lack of concern about body image and health during pregnancy linked to excessive gestational weight gain and small-for-gestational-age deliveries: the Japan Environment and Children’s Study

 

Group 2

Group 3

Maternal factors

RRR

95% CI

aRRR

95% CI

RRR

95% CI

aRRR

95% CI

Maternal age, y

 ≤ 19 (teenage mother)

1.47

1.26–1.73

1.06

0.89–1.27

1.90

1.58–2.28

1.51

1.22–1.86

 20–34

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 ≥ 35

0.59

0.56–0.62

0.69

0.65–0.72

0.87

0.82–0.92

0.87

0.82–0.92

BMI categories, kg/m2

 < 18.5 (underweight)

1.17

1.12–1.23

1.23

1.17–1.30

1.33

1.26–1.42

1.22

1.14–1.30

 18.5–24.9 (normal weight)

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 ≥ 25 (overweight)

0.41

0.38–0.44

0.41

0.37–0.44

1.06

0.99–1.14

0.95

0.88–1.03

Marital status

 Married

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 Single mother

1.48

1.36–1.60

1.10

1.01–1.21

1.58

1.43–1.75

1.30

1.15–1.45

Educational level

 High school or less

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 Vocational school/College

1.01

0.97–1.05

1.04

0.99–1.09

0.64

0.61–0.68

0.75

0.70–0.79

 University or higher

0.88

0.84–0.93

0.91

0.86–0.96

0.57

0.54–0.61

0.73

0.68–0.78

Weight loss methodsa

 None

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 Healthy method

1.36

1.31–1.41

1.38

1.33–1.45

0.67

0.64–0.70

0.71

0.67–0.75

 Unhealthy method

2.19

2.05–2.33

2.09

1.94–2.25

1.05

0.96–1.15

0.83

0.75–0.91

Total energy intake, kcal/d

 1st (lowest tertile)

1.04

1.00–1.09

0.98

0.94–1.03

1.18

1.12–1.25

1.07

1.01–1.14

 2nd

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 3rd

1.02

0.98–1.07

1.03

0.99–1.08

1.17

1.11–1.24

1.15

1.08–1.22

Physical activity, MET-min/d

 1st (lowest tertile)

0.97

0.92–1.01

0.98

0.93–1.03

1.07

1.01–1.13

1.01

0.95–1.08

 2nd

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 3rd

1.14

1.09–1.20

1.06

1.01–1.12

1.18

1.12–1.26

1.10

1.04–1.17

Smoking

 Never smoke

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 Quit

1.12

1.08–1.17

1.03

0.99–1.08

1.50

1.42–1.57

1.38

1.31–1.46

 Currently smoke

1.22

1.11–1.33

1.10

0.99–1.22

2.77

2.54–3.02

2.15

1.95–2.38

Alcohol

 Never drink

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 Quit

1.20

1.15–1.25

1.12

1.08–1.17

1.04

0.99–1.10

0.99

0.94–1.05

 Currently drink

1.06

0.99–1.13

1.12

1.04–1.20

0.97

0.89–1.06

0.97

0.88–1.06

Parity

 0

Ref.

 

Ref.

 

Ref.

 

Ref.

 

 1

0.68

0.66–0.71

0.76

0.73–0.80

1.20

1.14–1.27

1.16

1.09–1.23

 2 or more

0.53

0.50–0.56

0.60

0.57–0.64

1.34

1.26–1.42

1.21

1.13–1.30

Past medical history

 Anaemia

1.04

0.99–1.09

–

 

1.03

0.97–1.09

–

 

 Hypertension

0.46

0.39–0.54

0.67

0.56–0.79

1.23

1.08–1.40

1.13

0.98–1.30

 Diabetes

0.57

0.45–0.73

0.87

0.68–1.11

1.11

0.89–1.39

1.04

0.82–1.33

Previous caesarean delivery

0.70

0.65–0.76

0.97

0.90–1.06

1.51

1.41–1.63

1.44

1.32–1.56

Nausea and vomiting

0.99

0.94–1.04

1.05

1.00–1.11

0.89

0.84–0.95

0.93

0.87–0.99

Health guidance

0.89

0.83–0.94

0.92

0.86–0.98

1.01

0.94–1.08

0.99

0.91–1.07

  1. BMI body mass index, CI confidence interval, RRR crude relative risk ratio, aRRR adjusted relative risk ratio, MET metabolic equivalent
  2. Group 1 = health conscious; Group 2 = body-shape and health conscious; Group 3 = not body-shape or health conscious
  3. aHealthy method = eating less or reducing snacks, dieting, or exercising to lose weight; Unhealthy method = using medication, purging after meals, or smoking to lose weight
  4. Adjusted model included age, pre-pregnancy body mass index, marital status, parity, educational level, weight loss methods, total energy intake, physical activity, smoking and alcohol consumption habit, past medical history (hypertension, diabetes), previous caesarean delivery, pregnancy-related nausea and vomiting, and receipt of health guidance
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BMC Pregnancy and Childbirth

ISSN: 1471-2393

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