Skip to main content

Table 4 Subgroup analyses comparing milk intake and hip fracture risk for case-control and cohort studies

From: Dairy product consumption and risk of hip fracture: a systematic review and meta-analysis

 

Cohort studies (n = 9)

Case-control studies (n = 7)

 

n

RR

95% CI

I2 (%)

P a

P b

n

OR

95% CI

I2 (%)

P a

P b

Study quality

        

 Score ≥ 8

4

0.98

0.75–1.27

90.0

<0.01

0.90

4

0.80

0.67–0.95

10.0

0.34

0.05

 Score < 8

4

1.03

0.86–1.24

0.0

0.82

 

3

0.42

0.25–0.71

35.0

0.21

 

Region

            

 USA

4

1.00

0.96–1.03

0.0

0.84

0.44

1

1.10

0.63–1.94

NA

NA

0.04

 Europe

3

0.98

0.68–1.41

86.0

<0.01

 

3

0.77

0.65–0.90

0.0

0.39

 

 Asia

1

0.54

0.26–1.12

   

3

0.42

0.25–0.71

35.0

0.21

 

Sex

        

 Male

5

0.91

0.70–1.19

48.0

0.10

0.68

1

0.82

0.61–1.11

NA

NA

0.28

 Female

6

1.07

0.78–1.47

81.0

<0.01

 

4

0.78

0.53–1.14

58.0

0.07

 

 Both

3

0.91

0.70–1.18

23.8

0.23

 

2

0.46

0.25–0.85

44.0

0.18

 

No. of cases

        

 ≥ 1000

2

1.19

0.85–1.66

90.0

<0.01

0.16

1

0.71

0.58–0.87

NA

NA

0.21

 100–1000

4

1.00

0.82–1.21

0.0

0.57

 

4

0.83

0.65–1.06

24.0

0.27

 

 ≤ 100

6

0.79

0.60–1.04

46.0

0.10

 

2

0.28

0.15–0.55

0.0

0.84

 

Duration of follow-up years

        

 ≥ 10 years

5

1.02

0.84–1.25

86.0

<0.01

0.63

NA

NA

NA

NA

NA

NA

 < 10 years

3

0.89

0.62–1.29

0.0

0.98

 

NA

NA

NA

NA

NA

NA

Age

        

 ≥ 70

4

1.00

0.96–1.03

0.0

0.80

0.45

3

0.61

0.34–1.09

68.0

0.04

0.66

 < 70

5

0.89

0.66–1.02

83.0

<0.01

 

4

0.76

0.57–1.01

52.0

0.10

 

Adjustment for confounders

            

 Smoking

            

 Yes

5

1.06

0.87–1.29

85.0

<0.01

0.21

2

0.87

0.67–1.12

0.0

0.50

0.32

 No

3

0.78

0.55–1.11

0.0

0.52

 

5

0.60

0.42–0.88

60.0

0.04

 

Alcohol

            

 Yes

4

1.10

0.84–1.43

81.0

<0.01

0.18

2

0.87

0.67–1.12

0.0

0.50

0.32

 No

4

0.93

0.79–1.10

16.0

0.31

 

5

0.60

0.42–0.88

60.0

0.04

 

BMI

            

 Yes

5

1.00

0.77–1.29

79.0

<0.01

0.71

4

0.80

0.67–0.95

10.0

0.34

0.05

 No

3

0.99

0.96–1.03

0.0

0.83

 

3

0.42

0.25–0.71

35.0

0.21

 

Physical activity

            

 Yes

6

1.03

0.82–1.29

75.0

<0.01

0.47

2

0.72

0.52–1.00

37.0

0.21

0.93

 No

2

0.82

0.47–1.43

63.0

0.10

 

5

0.67

0.45–1.01

65.0

0.02

 

Sunlight exposure

            

 Yes

0

NA

NA

NA

NA

NA

2

0.74

0.63–0.88

0.0

0.43

0.67

 No

8

1.01

0.84–1.20

80.0

<0.01

 

5

0.62

0.38–1.01

67.0

0.02

 

Total energy intake

            

 Yes

5

1.11

0.91–1.35

86.0

<0.01

0.05

0

NA

NA

NA

NA

NA

 No

3

0.69

0.49–0.96

0.0

0.45

 

7

0.71

0.55–0.91

54.0

0.04

 

Calcium and vitamin D supplementation

            

 Yes

5

1.12

0.92–1.36

86.0

<0.01

0.04

0

NA

NA

NA

NA

NA

 No

3

0.69

0.50–0.95

0.0

0.47

 

7

0.71

0.55–0.91

54.0

0.04

 
  1. Abbreviations: N, the number of studies; CI, confidence interval; OR, odds ratio; RR, relative risk; NA, not applicable; BMI, body mass index. Pa, heterogeneity within each subgroup; Pb, heterogeneity between subgroups with meta-regression analysis