Table 2

Association between the TRPV1 585 Ile–Ile genotype and symptomatic or asymptomatic knee osteoarthritis (OA) in a crude meta-analysis and in pooled analysis

Groups comparedSample sizeSummary OR (95% CI) (crude Mantel–Haenzsel)p Value meta‑analysisHeterogeneity I2 p(Cochran's Q)Pooled analysis OR (95% CI)p Value pooled analysis
Any knee OA versus controls4368 cases, 3852 controls0.83 (0.73 to 0.95)0.0073I2 =0% p(Q)<0.390.84 (0.72 to 0.98)*<0.0277*
Symptomatic knee OA versus controls3270 cases, 3852 controls0.74 (0.64 to 0.87)0.00022I2 =0% p(Q)<0.660.76 (0.64 to 0.92)*<0.0042*
Asymptomatic knee OA versus controls1098 cases, 3852 controls0.99 (0.81 to 1.22)0.93I2 =0% p(Q)<0.671.01 (0.78 to 1.31)*<0.92*
Symptomatic versus asymptomatic knee OA3270 symptomatic cases, 1098 asymptomatic cases0.76 (0.59 to 0.99)0.0378I2 =0% p(Q)<0.870.74 (0.55 to 0.99)<0.0417
  • ORs refer to the risk of individuals carrying the TRPV1 585 Ile–Ile compared with Val–Ile and Val–Val individuals.

  • * Adjusted for age, sex and body mass index (BMI).

  • Adjusted for age, sex, BMI and Kellgren–Lawrence grade.

  • All estimates are also adjusted for relatedness between twins.