Participants with missing data on father’s occupational position (1,914), education (1,626) and height (3,109), or not followed-up for mortality (12), categories not mutually exclusive, were excluded from the analysis. In total, 18,393 men (84.0% of men at baseline) and 7,060 women (78.2% of women at baseline) were included in the analysis presented here. Those excluded tended to be shorter (169.5 cm vs. 171.2 cm, P<0.001), more likely to have a father with a manual occupation (57% vs. 54%, P=0.006), and less educated (31% vs. 29% with no higher secondary education, P <0.001). The excluded men were not different in age to those included (44.0 vs. 44.0 years, P =0.89), but excluded women were older than included women (43.0 vs. 42.7 years, P <0.01). For three individuals the specific cause of death was unknown and they have been excluded from the cause-specific analysis.
shows the sample characteristics. As expected, the cohorts have marked differences in father’s occupational position and education with Whitehall II being the more advantaged cohort. For father’s occupational position, the majority of the Whitehall II participants (60.9% of men and 50.6 % of women) reported non-manual occupations whereas the majority of the GAZEL participants (61.9% of men and 55.7% of women) reported their father to have a manual occupation. All three markers of early life socioeconomic circumstances were closely related. In both studies, participants whose father had a non-manual occupation or participants with a higher education tended to be taller (P <0.001, results not shown). Similarly, participants with a higher education were more likely to report father’s occupation as non-manual (P <0.001, results not shown).
Characteristics of Participants of the Whitehall II Study and the GAZEL Study
A total of 389 men and 185 women in Whitehall II and 772 men and 141 women in GAZEL died during the follow-up. The mortality rate for men was the same in both cohorts (3.3 per 1,000 person-years) but higher in Whitehall II than in GAZEL for women (3.5 vs. 1.7 per 1,000 person-years). Information on the underlying cause of death was available for 571 of the 574 deaths in Whitehall II participants and 716 out of 913 in GAZEL.
shows the mortality distribution across the measures of early life socioeconomic circumstances for all-cause mortality. As mortality was lower in the average-height category (mean±2cm) it was taken to be the reference category for height; for other indicators, non-manual father’s occupational position and university degree were the reference categories. In the analysis adjusted for age, sex and cohort, participants whose father had a manual occupation had a slightly higher risk of death (HR = 1.11; 95% CI: 1.00, 1.23) compared to those whose father’s had a non-manual occupation. The risk was attenuated after adjusting for education and height. The association between education and mortality was robust and only slightly attenuated after adjustment for height and father’s occupation. The test for trend suggested a linear association between education and mortality (P ≤0.001). The Cox regression suggested some evidence of higher mortality in the shorter-than-average (HR = 1.17; 95% CI: 1.02, 1.34) and taller-than-average individuals (HR = 1.16; 95% CI: 1.01, 1.34). These associations remained unchanged after adjustment for the other measures of early life socioeconomic circumstances.
Early life Socioeconomic Predictors of All-cause Mortality, the Whitehall II and GAZEL Studies (N=25,453)
shows analyses using cancer mortality as the outcome. The associations were largely similar to those for all-cause mortality. Participants whose father had a manual occupation had a 19% (95% CI: 1.01, 1.39) higher risk of dying from cancer. Compared to participants with a university qualification, those with less than higher secondary education had 60% (95% CI: 1.26, 2.04) higher risk of death. The U-shaped association between height and mortality was also evident (HR = 1.24; 95% CI: 1.01, 1.53 for the shorter-than-average and HR = 1.30; 95% CI: 1.05, 1.61 for the taller-than-average). The associations between height and cancer mortality were not reduced after adjusting for the other measures of early life socioeconomic circumstances.
Early life Socioeconomic Predictors of Cancer Mortality, the Whitehall II and GAZEL Studies (N=25,450)
presents the association between early life socioeconomic circumstances and CVD mortality, with CHD as a separate sub-category. The lowest education group had greater risk of CVD mortality in the fully adjusted model (HR = 1.41; 95% CI: 1.01, 1.97) and there was some evidence of a dose-response effect (P =0.06). Shorter-than-average individuals had a greater risk of CVD mortality (HR = 1.41; 95% CI: 1.03, 1.93) and there was also an indication of excess risk of CHD mortality (HR = 1.40; 95% CI: 0.94, 2.09). Similarly, there was some evidence of excess CVD (HR = 1.36; 95% CI: 0.98, 1.88) but not CHD (HR = 0.97; 95% CI: 0.62, 1.51) mortality among the taller-than-average individuals. Finally, presents the results for other causes of death, or non cancer and non CVD mortality. Although none of the results were significant at the P <0.05 level, the pattern of results was similar to that for all-cause mortality, except for height which tended to be inversely associated with mortality.
Early life Socioeconomic Predictors of CVD and CHD Mortality, the Whitehall II and GAZEL Studies (N=25,450)
Early life Socioeconomic Predictors of Non Cancer and Non CVD Mortality, the Whitehall II and GAZEL Studies (N=25,450)