RESEARCH - Autoimmune diseases co-occurring within individuals and within families: a systematic review

[Guest guest]

Epidemiology. 2006 Mar;17(2):202-17.

Autoimmune diseases co-occurring within individuals and within

families: a systematic review.

Somers EC, SL, Smeeth L, Hall AJ.

Department of Infectious and Tropical Diseases, London School of

Hygiene & Tropical Medicine, London, UK.

BACKGROUND: Autoimmune diseases have been observed to coexist both

within individuals and within families. It is unclear whether clinical

reports of comorbid autoimmune diseases represent chance findings or

true associations. This systematic review evaluates the current level

of evidence on the coexistence of selected autoimmune diseases within

individuals and families. We reviewed the associations among 4

TH1-associated autoimmune diseases: insulin-dependent diabetes

mellitus, autoimmune (Hashimoto) thyroiditis, rheumatoid arthritis,

and multiple sclerosis. METHODS: Studies quantifying the coexistence

between the selected diseases, published through March 2004, were

identified from Medline and Embase searches. Study eligibility was

determined on the basis of preestablished criteria, and relevant data

were extracted according to a fixed protocol. We determined the

prevalence of comorbid autoimmune disease according to index disease

and then compiled summary statistics. Heterogeneity among studies was

assessed by exact likelihood ratio tests and Monte Carlo inference.

RESULTS: We found 54 studies that met the eligibility criteria. Of

these, 52 studies examined the coexistence of disease within

individuals and 9 studies examined within-family associations. The

majority of studies were uncontrolled and did not account for

confounding factors. There was substantial evidence for heterogeneity

among studies. Although inconclusive, the data appear to support an

increased prevalence of autoimmune thyroiditis among patients with

rheumatoid arthritis and those with insulin-dependent diabetes

mellitus, and an inverse association between rheumatoid arthritis and

multiple sclerosis.

CONCLUSION: Although the available evidence does not permit firm

conclusions regarding comorbidities among the selected autoimmune

diseases, results are sufficiently suggestive to warrant further

study.

PMID: 16477262

http://www.ncbi.nlm.nih.gov/pubmed/16477262

--

Not an MD