| IQ quintile | p Value for linear trend | HR per 1 SD increase in IQ* | |||||
| 1 (⩽86) | 2 (87–99) | 3 (100–10) | 4 (111–22) | 5 (>122) | |||
| No of deaths/no of men | 70/817 | 41/759 | 53/814 | 46/934 | 31/992 | ||
| Mortality rate per 1000 person-years | 5.8 | 3.6 | 4.4 | 3.3 | 2.1 | ||
| Adjustment for confounding factors† | |||||||
| Age | 2.97 (1.94 to 4.54) | 1.86 (1.16 to 2.97) | 2.24 (1.44 to 3.50) | 1.68 (1.07 to 2.66) | 1.0 (ref) | <0.001 | 0.71 (0.63 to 0.81) |
| Age, rank | 2.47 (1.60 to 3.84) | 1.61 (1.00 to 2.60) | 2.05 (1.31 to 3.21) | 1.58 (1.00 to 2.50) | 1.0 | <0.001 | 0.76 (0.67 to 0.86) |
| Age, ethnicity | 2.24 (1.42 to 3.52) | 1.58 (0.98 to 2.55) | 2.06 (1.32 to 3.23) | 1.62 (1.03 to 2.57) | 1.0 | 0.002 | 0.79 (0.69 to 0.90) |
| Adjustment for age and mediating factors† | |||||||
| Age, depression | 2.86 (1.87 to 4.38) | 1.80 (1.13 to 2.88) | 2.25 (1.44 to 3.52) | 1.67 (1.06 to 2.63) | 1.0 | <0.001 | 0.72 (0.64 to 0.82) |
| Age, body mass index | 2.91 (1.90 to 4.46) | 1.86 (1.16 to 2.97) | 2.20 (1.41 to 3.44) | 1.67 (1.06 to 2.64) | 1.0 | <0.001 | 0.72 (0.64 to 0.81) |
| Age, pulse rate | 2.86 (1.87 to 4.38) | 1.79 (1.12 to 2.87) | 2.21 (1.42 to 3.44) | 1.68 (1.06 to 2.65) | 1.0 | <0.001 | 0.72 (0.64 to 0.81) |
| Age, posttraumatic stress disorder | 2.84 (1.85 to 4.35) | 1.80 (1.12 to 2.87) | 2.22 (1.42 to 3.46) | 1.66 (1.05 to 2.62) | 1.0 | <0.001 | 0.73 (0.64 to 0.82) |
| Age, somatic disease | 2.84 (1.86 to 4.35) | 1.81 (1.13 to 2.90) | 2.21 (1.41 to 3.44) | 1.68 (1.06 to 2.65) | 1.0 | <0.001 | 0.73 (0.64 to 0.82) |
| Age, marital status | 2.84 (1.85 to 4.34) | 1.86 (1.17 to 2.98) | 2.23 (1.43 to 3.48) | 1.72 (1.09 to 2.72) | 1.0 | <0.001 | 0.73 (0.65 to 0.83) |
| Age, alcohol consumption | 2.79 (1.82 to 4.28) | 1.75 (1.09 to 2.80) | 2.11 (1.35 to 3.29) | 1.60 (1.01 to 2.53) | 1.0 | <0.001 | 0.73 (0.64 to 0.82) |
| Age, systolic blood pressure | 2.83 (1.85 to 4.34) | 1.84 (1.15 to 2.94) | 2.20 (1.41 to 3.43) | 1.69 (1.07 to 2.67) | 1.0 | <0.001 | 0.73 (0.64 to 0.82) |
| Age, diastolic blood pressure | 2.79 (1.82 to 4.28) | 1.81 (1.13 to 2.89) | 2.20 (1.41 to 3.43) | 1.69 (1.07 to 2.67) | 1.0 | <0.001 | 0.73 (0.65 to 0.83) |
| Age, blood glucose | 2.73 (1.78 to 4.19) | 1.82 (1.14 to 2.91) | 2.21 (1.42 to 3.45) | 1.67 (1.06 to 2.63) | 1.0 | <0.001 | 0.74 (0.65 to 0.83) |
| Age, generalised anxiety disorder | 2.71 (1.77 to 4.15) | 1.75 (1.10 to 2.81) | 2.23 (1.43 to 3.48) | 1.68 (1.07 to 2.66) | 1.0 | <0.001 | 0.74 (0.66 to 0.84) |
| Age, smoking habit | 2.55 (1.66 to 3.93) | 1.61 (1.00 to 2.57) | 2.02 (1.29 to 3.16) | 1.58 (1.00 to 2.49) | 1.0 | <0.001 | 0.75 (0.66 to 0.85) |
| Age, FEV1 | 2.42 (1.57 to 3.73) | 1.62 (1.01 to 2.60) | 2.06 (1.32 to 3.22) | 1.59 (1.01 to 2.52) | 1.0 | <0.001 | 0.76 (0.67 to 0.87) |
| Age, occupational prestige | 2.30 (1.46 to 3.76) | 1.50 (0.92 to 2.45) | 1.91 (1.21 to 3.01) | 1.53 (0.96 to 2.43) | 1.0 | 0.001 | 0.77 (0.68 to 0.88) |
| Age, educational grade | 2.05 (1.26 to 3.32) | 1.33 (0.80 to 2.22) | 1.72 (1.06 to 2.77) | 1.42 (0.88 to 2.28) | 1.0 | 0.01 | 0.79 (0.69 to 0.92) |
| Age, family income | 1.74 (1.12 to 2.71) | 1.25 (0.78 to 2.01) | 1.72 (1.10 to 2.69) | 1.48 (0.93 to 2.34) | 1.0 | 0.07 | 0.86 (0.75 to 0.98) |
| Age, socioeconomic mediating factors‡ | 1.39 (0.85 to 2.29) | 1.02 (0.61 to 1.71) | 1.46 (0.90 to 2.35) | 1.33 (0.83 to 2.13) | 1.0 | 0.54 | 0.92 (0.79 to 1.07) |
| Age, all mediating factors§ | 1.24 (0.74 to 2.06) | 0.98 (0.58 to 1.65) | 1.43 (0.89 to 2.31) | 1.32 (0.82 to 2.12) | 1.0 | 0.95 | 0.97 (0.82 to 1.13) |
| Age and all confounding and mediating factors (without education) | 1.10 (0.67 to 1.83) | 0.91 (0.54 to 1.53) | 1.44 (0.90 to 2.29) | 1.30 (0.81 to 2.08) | 1.0 | 0.67 | 1.01 (0.86 to 1.18) |
| Age and all confounding and mediating factors (with education) | 0.94 (0.55 to 1.61) | 0.80 (0.47 to 1.37) | 1.30 (0.80 to 2.11) | 1.21 (0.75 to 1.95) | 1.0 | 0.31 | 1.06 (0.90 to 1.26) |
*Hazard ratios (HR) for the relation of a 1 SD increase in IQ with all-cause mortality. †Confounding and mediating factors are ordered according to increasing attenuating effect on the IQ–mortality relation (based on the HR for a 1 SD increase in IQ in relation to all-cause mortality). ‡Socioeconomic mediating factors are occupational prestige, educational grade and family income. §Mediating factors are all those mediating factors listed in the table.