Institutionen för folkhälsovetenskap / Department of Public Health Sciences
Abstract
The general aim of the thesis was to study how socioeconomic and
behaviour-related factors measured in childhood, late adolescence or
adulthood are related to coronary heart diseae (CHD) and stroke in middle
age among Swedish men. The life course approach was central to the aim,
and the potential impact of socioeconomic differences in adulthood among
the men was considered throughout.
The thesis was based on the 1969 conscription cohort, i.e. a cohort of
almost 50 000 Swedish men who in 1969/70 went through a conscription
examination for compulsory military service. They were between 18 and 20
years of age at that time. Information from physiological assessments,
cognitive tests, and questionnaires were used in combination with (1)
register-based indicators of social circumstances in childhood and
adulthood, and information on educational level, and (2) register-based
information on fatal and non-fatal events of CHD and stroke between 1971
and 2007. Multivariable regression methods were used to analyse data.
In study I and II, higher levels of BMI and blood pressure in late
adolescence were shown to be significantly associated with increased
risks of CHD and stroke before 55 years of age. Men with higher BMI were
more likely to be in lower socioeconomic positions later in adulthood,
but differences among the men in adult socioeconomic positions did not
seem to affect, i.e. mediate or modify, associations between BMI/blood
pressure in late adolescence and CHD/stroke in middle age.
BMI, smoking, and body height in late adolescence were shown, in study
III, to contribute to explain associations between childhood
socioeconomic position and CHD/stroke in middle age. Possibly, study III
also showed that childhood social disadvantage may have an independent
long-term effect on CHD and stroke in middle age. In study IV, it was
shown that large parts of the associations between educational attainment
and CHD/stroke in middle age may be explained by confounding from social
and behaviour-related risk factors measured in childhood and late
adolescence.
Thus, it was shown that factors in childhood and adolescence may be
critical in relation to CHD and stroke in middle age among men. Increased
risks of CHD and stroke could be an effect of disadvantages in childhood,
acting through biological and/or behavioural development early in life.
The findings may also be compatible with the view that social
disadvantages and adverse behavioural responses from childhood and
onwards increase risks of disease, such as CHD and stroke, in a
cumulative manner over the life course. Moreover, the findings showed
that such accumulation of cardiovascular risk may be most prevalent among
men born to parents of lower socioeconomic positions and among men who
attain lower educational levels; these are the same categories of men
that tend to end up in lower socioeconomic positions in adulthood. In
this way, social differences in cardiovascular disease among adult men
could possibly be explained by confounding from factors earlier in life