Approved Research

Association of depressive symptoms with risk of all-cause mortality, cause-specific mortality and morbidity.

Lay summary

We seek to use the unprecedented power and richness of data in UK Biobank to investigate the relationship between depressive symptoms and risk of multiple chronic diseases.

More than 264 million people worldwide are affected by depression, and this burden has increased over the past 10 years. Chronic diseases are the leading cause of death and among the top causes globally of premature years of life lost. Links between chronic diseases and depressive disorders have been recognized for more than 300 years with numerous studies reporting increased risk of chronic diseases in individuals with depressive disorders. However, limitations of previous studies include i) involvement of a small numbers of participants and ii) insufficient examination of the influence of other known risk factors. Furthermore, few past studies have used genetic information to assess the causal nature of any association.

We plan to use data in UK Biobank to better quantify the observed association between depressive symptoms and risk of multiple chronic diseases. Assuming an association is observed, we also aim to use the genetic information available in UKBiobank participants to help determine whether the nature of this association is causal, by examining whether individuals with genetic predisposition to elevated depressive symptoms are also at increased risk of multiple chronic diseases.

The specific research objectives are:

(1) To characterise and compare the associations of depressive symptoms with future risk of multiple chronic diseases.

(2) To examine the relationship between depressive symptoms and other risk factors, and check whether any of these other risk factors impact on the observed relationship between depressive symptoms and multiple chronic diseases.

(3) To provide evidence for any causal association between depressive symptoms and disease, thereby eliminating other potential reasons for the association: i.e. that risk is being effected by other co-occurring risk factors or that an individual's experience of depressive symptoms may to be linked to underlying unknown diseases (a phenomenon known as reverse causality).

Results can advance understanding of factors related to levels of depressive symptoms and clarify the relative importance of depressive symptoms on disease risk. This, in turn, will inform future research which could potentially impact on clinical practice to reduce burden of both depression and chronic diseases.