6(30)
2
How sickness absence can be inherited
A reasonable determinant for explaining an intergenerational correlation
in sickness absence is the health status among parents and their children.
Some diseases associated with sickness absence are genetic and children
may be genetically predisposed to develop them. However, most diseases
have complex causes; genetic susceptibility can act in combination with
environmental factors and environmental factors affect people differently
depending on their genetics. For example, Hedström et al. (2011) found
that the risk of developing multiple sclerosis among individuals with a
specific genetic variant is heavily influenced by smoking, but for
individuals without this gene variant, smoking is not nearly as important.
Correspondingly, although the parent has a genetic disease, the child does
not necessarily develop the same disease. Instead, the risk of developing
the disease for which one has a genetic predisposition mostly depends on
the environment and the environment mostly changes with time.
The causes of disease are not equal to the causes of sick leave. Most people
who have a diagnosed disease are not on sick leave (Wikman, Marklund
and Alexanderson, 2005) and people are eligible for sick leave benefits
and allowances only if the disease or injury impairs their ability to work
by at least 25 per cent. For example, the ability of a person to carry out
professional work when he or she has multiple sclerosis depends on his or
her functioning, the profession and the working conditions. Thus, sickness
absence is one possible social consequence of disease or injury in terms of
impaired work ability.
9
The medical progress and the possibilities to adjust
the working environment for different types of dysfunctions are, of course,
crucial for explaining the sickness absence level. Thus, the extent of
intergenerational mobility in any aspect is contingent on the context in
which it is studied.
In addition to family-common health (the transmission of health through
behaviour and genetics), there are several other channels through which
sick leave can be transmitted from parent to child. One is the fact that
children often inherit their parents’ choice of education and occupation
(e.g., Breen, 2004; Holmlund, Lindahl and Plug, 2011). Different
professions (with corresponding working environments) are associated with
different levels of sickness absence. In general, the longer the education
required for an occupation, the lower the average level of sickness absence
(Försäkringskassan, 2010). The extent to which this observation is
explained by differences in work-related exposure, in possibilities of
adjustments at work, or by health selection into certain occupations is
unclear from the literature.
9
For a further discussion on this subject, see Marmot et al. (1995).
