Table 1. Results of subgroup analysis stratified by study and population characteristics and type of dairy.
| Cross-sectional/case-control studies (N = 16) |
Prospective cohort studies (N = 7) |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| N | OR (95% CI) | Pa | I2(%) | Pb | N | RR (95% CI) | Pa | I2(%) | Pb | ||
| Region | |||||||||||
| Asia-pacific | 6 | 0.83 (0.76–0.91) | 0.77 | 0.0 | 3 | 0.80 (0.66–0.95) | 0.85 | 0.0 | |||
| Europe | 5 | 0.81 (0.53–1.25) | 0.003 | 75.6 | 0.83c | 2 | 0.89 (0.79–1.00) | 0.90 | 0.0 | 0.39c | |
| USA | 5 | 0.83 (0.60–1.15) | 0.005 | 73.2 | 0.89c | 2 | 0.75 (0.51–1.12) | 0.10 | 63.9 | 0.98c | |
| Sex | |||||||||||
| Men | 6 | 0.70 (0.48–1.04) | 0.000 | 77.5 | 0 | NA | NA | NA | |||
| Women | 5 | 0.92 (0.59–1.44) | 0.009 | 70.3 | 0.41d | 0 | NA | NA | NA | NA | |
| Both | 10 | 0.86 (0.76–0.97) | 0.16 | 31.0 | 0.63d | 7 | 0.86 (0.79–0.92) | 0.65 | 0.0 | NA | |
| Duration of follow-up | |||||||||||
| ≥9 years | NA | NA | NA | NA | NA | 4 | 0.86 (0.78–0.95) | 0.31 | 15.7 | 0.52 | |
| <9 years | NA | NA | NA | NA | NA | 3 | 0.81 (0.68–0.96) | 0.94 | 0.0 | ||
| Dairy ascertainment | |||||||||||
| Self-report | 8 | 0.85 (0.64–1.14) | 0.000 | 0.70 | 4 | 0.88 (0.79–0.99) | 0.91 | 0.0 | 0.49 | ||
| Interview or food diary | 7 | 0.82 (0.75–0.91) | 0.69 | 0.0 | 3 | 0.82 (0.71–0.94) | 0.22 | 34.3 | |||
| MetS assessment | |||||||||||
| NCEP ATP-III | 10 | 0.85 (0.75–0.95) | 0.04 | 48.0 | 0.56 | 4 | 0.86 (0.78–0.95) | 0.82 | 0.0 | 0.77 | |
| Other | 5 | 0.65 (0.34–1.23) | 0.002 | 76.7 | 3 | 0.76 (0.57–1.02) | 0.20 | 37.1 | |||
| Type of dairy | |||||||||||
| Total dairy | 12 | 0.81 (0.70–0.94) | 0.03 | 49.4 | 0.45 | 6 | 0.86 (0.79–0.92) | 0.65 | 0.0 | 0.20 | |
| Milk | 6 | 0.90 (0.74–1.11) | 0.003 | 71.9 | 3 | 0.75 (0.63–0.89) | 0.92 | 0.0 | |||
| Adjustment | |||||||||||
| Smoking | Yes | 12 | 0.80 (0.69–0.93) | 0.01 | 55.0 | 0.46 | 7 | 0.86 (0.79–0.92) | 0.65 | 0.0 | NA |
| No | 4 | 0.93 (0.63–1.37) | 0.02 | 69.2 | 0 | NA | NA | NA | |||
| Alcohol | Yes | 6 | 0.77 (0.67–0.88) | 0.21 | 30.5 | 0.36 | 4 | 0.78 (0.66–0.92) | 0.59 | 0.0 | 0.25 |
| No | 10 | 0.88 (0.72–1.08) | 0.004 | 63.3 | 3 | 0.88 (0.81–0.95) | 0.75 | 0.0 | |||
| Physical activity | Yes | 11 | 0.86 (0.75–0.99) | 0.003 | 62.4 | 0.32 | 7 | 0.86 (0.79–0.92) | 0.65 | 0.0 | NA |
| No | 5 | 0.70 (0.51–0.96) | 0.15 | 50.4 | 0 | NA | NA | NA | |||
| Education | Yes | 6 | 0.90 (0.73–1.10) | 0.18 | 33.8 | 0.54 | 4 | 0.83 (0.75–0.92) | 0.38 | 2.5 | 0.50 |
| No | 10 | 0.80 (0.68–0.94) | 0.003 | 63.9 | 3 | 0.88 (0.79–0.99) | 0.76 | 0.0 | |||
| Dietary energy | Yes | 13 | 0.78 (0.67–0.91) | 0.02 | 50.2 | 0.22 | 6 | 0.83 (0.76–0.92) | 0.63 | 0.0 | 0.45 |
| No | 3 | 0.99 (0.74–1.32) | 0.01 | 77.5 | 1 | 0.89 (0.79–1.00) | NA | NA | |||
| Dietary fat | Yes | 2 | 0.73 (0.59–0.90) | 0.15 | 52.4 | 0.42 | 3 | 0.80 (0.59–1.07) | 0.21 | 35.4 | 0.75 |
| No | 14 | 0.85 (0.74–0.99) | 0.007 | 54.9 | 4 | 0.85 (0.77–0.93) | 0.81 | 0.0 | |||
| Meat | Yes | 2 | 0.80 (0.70–0.93) | 0.44 | 0.0 | 0.76 | 3 | 0.82 (0.71–0.94) | 0.22 | 34.3 | 0.49 |
| No | 14 | 0.83 (0.72–0.97) | 0.001 | 62.1 | 4 | 0.88 (0.79–0.99) | 0.91 | 0.0 | |||
| Whole/refined grain | Yes | 1 | 0.81 (0.73–0.93) | NA | NA | 0.94 | 3 | 0.82 (0.71–0.94) | 0.22 | 34.3 | 0.49 |
| No | 15 | 0.83 (0.71–0.96) | 0.001 | 60.0 | 4 | 0.88 (0.79–0.99) | 0.91 | 0.0 | |||
| Dietary fiber | Yes | 3 | 0.88 (0.74–1.05) | 0.40 | 0.0 | 0.78 | 2 | 0.58 (0.38–0.89) | 0.88 | 0.0 | 0.13 |
| No | 13 | 0.82 (0.70–0.95) | 0.001 | 63.1 | 5 | 0.87 (0.80–0.93) | 0.92 | 0.0 | |||
| Fruit and vegetable | Yes | 2 | 0.80 (0.70–0.93) | 0.44 | 0.0 | 0.76 | 3 | 0.82 (0.71–0.94) | 0.22 | 0.0 | 0.49 |
| No | 14 | 0.83 (0.72–0.97) | 0.001 | 62.1 | 4 | 0.88 (0.79–0.99) | 0.91 | 0.0 | |||
CI, confidence interval; NA, not applicable; NCEP ATP-III, Adult Treatment Panel III of the National Cholesterol Education Program; OR, odds ratio; RR, relative risk.
aP value for heterogeneity among studies.
bP value for heterogeneity between groups according to meta-regression.
cAsia-pacific studies as a reference group.
dMale data as reference group.