Investigating the role of pain-modulating pathway genes in musculoskeletal pain.

AIMS: The aim of this study was to determine if genetic variation in the pain-modulating gene DREAM and its pathway genes influence susceptibility to reporting musculoskeletal pain in the population. METHODS: Pairwise tag single nucleotide polymorphisms (SNPs) in DREAM, PDYN and OPRK1 were genotyped in a UK population-based discovery cohort in whom pain was assessed using blank body manikins at three time points. Depression and anxiety symptoms were assessed at the first time point. Zero-inflated negative binomial regression was used to test for association between SNPs and the maximum number of pain sites reported (0-29) across the three time points. Significantly associated SNPs (p < 0.05) were subsequently genotyped for validation in a cohort of European men with pain assessed at two time points. RESULTS: Thirty-five SNPs were genotyped in 1055 subjects, of whom 83% reported pain, in the discovery cohort. SNPs in each gene were associated with the maximum number of pain sites reported, were independent of symptoms of anxiety and depression and had a significant cumulative effect (p = 7.0 × 10(-5) ). Significantly associated SNPs were successfully genotyped in 1733 men, 76% of whom reported pain, in the validation cohort, but did not show significant association with the number of pain sites. CONCLUSIONS: Genetic variation in the DREAM pathway genes was associated with the extent of pain reporting in a population-based cohort. These findings were not replicated in a single independent cohort; however, given the potential of this pathway as a therapeutic target, further investigation in additional cohorts is warranted.

Lifetime body mass index, other anthropometric measures of obesity and risk of knee or hip osteoarthritis in the GOAL case-control study.

OBJECTIVE: To examine the risk of large joint osteoarthritis (OA) in those becoming overweight during early adult life, and to assess the risks associated with high body mass index (BMI) and other anthropometric measures of obesity. METHODS: BMI, waist and hip circumference were measured in the GOAL case-control study comprising hip OA cases (n=1007), knee OA cases (n=1042) and asymptomatic controls (n=1121). Retrospective estimates of lifetime weight, body shape and other risk factors were collected using an interview-lead questionnaire. Odds ratios (ORs), adjusted OR (aOR), 95% confidence intervals (CIs) and P values were calculated using logistic regression analysis. RESULTS: BMI was associated with knee OA (aOR 2.68, 95% CI 2.33-3.09, P-trend<0.001) and hip OA (aOR 1.65, 95% CI 1.46-1.87, P-trend<0.001). Those who became overweight earlier in adulthood showed higher risks of lower limb OA (P-trend<0.001 for knee OA and hip OA). Self-reported body shape was also associated with knee OA and hip OA, following a similar pattern to current and life-course BMI measures. Waist:hip ratio (WHR) at time of examination did not associate with OA independently of BMI, except in women-only analysis. Waist circumference was associated with lower limb OA risk. CONCLUSIONS: Becoming overweight earlier in adult life increased the risks of knee OA and hip OA. Different distribution patterns of adiposity may be related to OA risk in women.