Association of medical, physiological, behavioural and socio-economic factors with elevated mortality in men of Irish heritage in West Scotland.

BACKGROUND: Men with patrilineal Irish descent from the immigrations of the nineteenth and twentieth centuries have higher death rates from 'all-causes' and, specifically, cardiovascular disease (CVD) than the general population of the West of Scotland.
METHODS: A total of 5766 male employees from 27 workplace settings were examined between 1970 and 1973. Surname analysis identified 15 per cent of these men as of patrilineal Irish heritage. For those who have since died, the date and cause of death was obtained. Cox's proportional hazards model was used to compare the mortality risk of those with Irish and non-Irish surnames, and to investigate established medical, physiological, behavioural and socio-economic risk factors (acting in early and later life) as possible explanations for this excess mortality.
RESULTS: The relative risk of death from all causes for the Irish of 1.26 (95 per cent confidence interval (CI) (1.12, 1.43)) was reduced to 1.12 (95 per cent CI (0.99, 1.26)) by including established risk factors in the model. The relative risk of CVD mortality of 1.51 (95 per cent CI (1.29, 1.77)) for the Irish was reduced to 1.35 (95 per cent CI (1.14, 1.58)) by the same adjustments. The elevated all-cause mortality of the Irish was mainly attributable to cardiovascular deaths.
CONCLUSIONS: Cigarette smoking was only able to 'explain' a small amount of the excess all-cause and CVD mortality of men with patrilineal Irish descent. Relative deprivation during childhood and adulthood contributed to the high Irish mortality. However, there remains a substantial excess of premature deaths among Irish men which is unaccounted for by established risk factors.