Widowed versus married | Divorced versus married | Lifelong single versus married | |||||

Stratified analysis: Relative risk (95% CI) Number of studies | Meta-regression coefficient (95% CI) p value | Stratified analysis: Relative risk (95% CI) Number of studies | Meta-regression coefficient (95% CI) p-value | Stratified analysis: Relative risk (95% CI) Number of studies | Meta-regression coefficient (95% CI) p value | ||

Method of case ascertainment | Clinical assessment | 1.20 (1.02 to 1.41) n=9 | b=−0.06 (−0.18 to 0.05) p=0.29 | 0.99 (0.71 to 1.37) n=7 | b=0.34 (0.06 to 0.62) p=0.02 | 1.42 (1.07 to 1.90) n=6 | b=−0.27 (−0.55 to 0.01) p=0.06 |

Clinical registers | 1.12 (1.07 to 1.18) n=2 | 1.11 (0.52 to 2.38) n=2 | 1.23 (1.17 to 1.29) n=2 | ||||

Study type | Cohort | 1.10 (1.05 to 1.28) n=7 | b=0.28 (0.09 to 0.46) p=0.004 | 1.16 (0.87 to 1.55) n=6 | b=−0.83 (−1.69 to 0.03) p=0.06 | 1.24 (1.17 to 1.30) n=5 | b=0.08 (−0.45 to 0.62) p=0.76 |

Case–control/cross-sectional | 1.39 (1.16 to 1.67) n=4 | 0.55 (0.23 to 1.31) n=3 | 1.21 (0.67 to 2.18) n=3 | ||||

Global quality score | Higher quality ≥6 | 1.13 (1.02 to 1.31) n=4 | b=0.08 (-0.06 to 0.23) p=0.27 | 1.16 (0.83 to 1.62) n=4 | b=−0.40 (-0.88 to 0.08) p=0.10 | 1.26 (1.09 to 1.45) n=3 | b=0.20 (-0.17 to 0.57) p=0.29 |

Lower quality <6 | 1.22 (0.96 to 1.54) n=7 | 0.88 (0.54 to 1.44) n=5 | 1.33 (0.92 to 1.92) n=5 | ||||

Increase in quality by one point | b=−0.04 (−0.08 to −0.002) p=0.04 n=11 | b=0.12 (0.01 to 0.24) p=0.04 n=9 | b=−0.05 (−0.13 to 0.03) p=0.21 n=8 | ||||

Time period | Mean DoB before 1927 | 1.11 (0.93 to 1.31) n=6 | b=0.15 (−0.14 to 0.43) p=0.32 | 0.98 (0.71 to 1.37) n=6 | b=0.35 (0.08 to 0.63) p=0.01 | 1.40 (1.06 to 1.85) n=5 | b=−0.22 (−0.50 to 0.06) p=0.13 |

Mean DoB after 1927 | 1.23 (1.06 to 1.43) n=5 | 1.08 (0.50 to 2.35) n=3 | 1.24 (0.94 to 1.62) n=3 | ||||

Mean year of birth 10 years later | b=0.08 (−0.08 to 0.23) p=0.34 n=11 | b=0.24 (0.01 to 0.47) p=0.04 n=9 | b=−0.15 (−0.33 to 0.02) p=0.09 n=8 |

Figures are based on random-effects meta-analysis.

DoB, date of birth.