Table 2: Prevalence ratio (PR), 95% confidence intervals (95% CI)

and p-value for test of trend for acne by categories of milk intake among the girls in the GUTS cohort at baseline, 1996, USA

     Servings (right)

                                                    Milk types(below)                                                                 

<=1/week

2 - 6/week

1/day

2 or more/day

p-value for test of trend

Total milk

Cases/Total

220/370

542/824

490/720

1336/1842 

Age-adjusted PR

1.00

1.11

1.15

1.23

<0.001

95% CI

1.01, 1.23

1.05, 1.27

1.12, 1.34

Multivariate PR

1.00

1.13

1.17

1.2

<0.001

95% CI

1.02, 1.25

1.05, 1.29

1.09, 1.31

Whole milk

Cases/Total

216/363

241/362

212/317

464/652

Age adjusted PR

1.00

1.14

1.15

1.21

<0.001

95% CI

1.02, 1.27

1.02, 1.28

1.09, 1.33

Multivariate PR

1.00

1.17

1.22

1.19

<0.001

95% CI

1.04, 1.32

1.08, 1.37

1.06, 1.32

Low Fat milk

Cases/Total

215/362

115/185

108/161

327/449

Age adjusted PR

1.00

1.06

1.15

1.24

<0.001

95% CI

0.92, 1.22

1.01, 1.32

1.12, 1.37

Multivariate PR

1.00

1.04

1.16

1.17

0.002

95% CI

0.89, 1.21

1.00, 1.35

1.04, 1.31

Skim milk

Cases/Total

215/361

153/218

150/220

531/722

Age adjusted PR

1.00

1.18

1.14

1.24

<0.001

95% CI

1.05, 1.34

1.00, 1.29

1.13, 1.37

Multivariate PR

1.00

1.2

1.08

1.19

<0.001

95% CI

1.04, 1.37

0.94, 1.24

1.08, 1.31

PR = prevalence ratio; CI = confidence interval.    Multivariate PR of acne for categories of intakes adjusted for age, height and energy intake.