Journal article
Interleukin-18 polymorphism and physical functioning in older people: a replication study and meta-analysis
The journals of gerontology. Series A, Biological sciences and medical sciences, Vol.64(11), pp.1177-1182
11/2009
DOI: 10.1093/gerona/glp092
PMCID: PMC2981454
PMID: 19633236
Abstract
Levels of the proinflammatory cytokine interleukin-18 (IL-18) are raised in old age and are associated with reduced physical functioning. Previous studies have indicated that the C allele of the rs5744256 polymorphism in the IL-18 gene is strongly associated with reduced circulating IL-18 levels. This variant has previously been associated with improved locomotor performance in old age, but the finding requires independent replication.
We examined the association between the IL-18 polymorphism rs5744256 and physical functioning in three cohorts with a total of 4,107 participants aged 60-85 years: the English Longitudinal Study of Ageing, Caerphilly, and Boyd Orr. We meta-analyzed (N = 6,141) the results with data from the original paper reporting this association: Iowa-Established Populations for Epidemiological Study of the Elderly and InCHIANTI cohorts. Physical functioning was assessed by timed walks or the get up and go test. As locomotor performance tests differed between the cohorts and the distributions of times to complete the test (in seconds) were positively skewed, we used the reciprocal transformation and computed study-specific z scores.
Based on the three new studies, the estimated linear regression coefficient per C allele was 0.011 (95% confidence interval [95% CI]: -0.04 to 0.06). A meta-analysis that pooled the data from all studies showed weak evidence of an effect, with a regression coefficient of 0.047 (95% CI: 0.010 to 0.083).
We did not replicate an association between the IL-18 rs5744256 polymorphism and the physical function in people aged 60-85 years. However, pooling data from all studies suggested a weak association of the C allele of the rs5744256 single nucleotide polymorphism on improving walking times in old age.
Details
- Title: Subtitle
- Interleukin-18 polymorphism and physical functioning in older people: a replication study and meta-analysis
- Creators
- Kate Thomas - University of BristolSajjad Rafiq - University of PlymouthTimothy M Frayling - University of PlymouthShah Ebrahim - London School of Hygiene & Tropical MedicineMeena Kumari - Department of Epidemiology and Public Health, UCL, UKJohn Gallacher - Cardiff UniversityLuigi Ferrucci - National Institute on AgingStefania Bandinelli - Azienda Sanitaria di FirenzeRobert B Wallace - University of IowaDavid Melzer - University of PlymouthRichard M Martin - Medical Research CouncilYoav Ben-Shlomo - Medical Research Council
- Resource Type
- Journal article
- Publication Details
- The journals of gerontology. Series A, Biological sciences and medical sciences, Vol.64(11), pp.1177-1182
- DOI
- 10.1093/gerona/glp092
- PMID
- 19633236
- PMCID
- PMC2981454
- NLM abbreviation
- J Gerontol A Biol Sci Med Sci
- ISSN
- 1079-5006
- eISSN
- 1758-535X
- Grant note
- R01AG1764406S1 / NIA NIH HHS Medical Research Council GR063779FR / Wellcome Trust GR068468MA / Wellcome Trust British Heart Foundation G0600705 / Medical Research Council
- Language
- English
- Date published
- 11/2009
- Academic Unit
- Epidemiology; Injury Prevention Research Center; Internal Medicine
- Record Identifier
- 9984364409702771
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