Table 2a

Results from logistic regression where self-reported diagnosis of a thyroid condition was regressed on urinary fluoride (Cycles 2 and 3) and fluoride concentration of tap water (Cycle 3)

Predictor variableCycle 2 of CHMSCycle 3 of CHMS
Unadjusted†  estimates for fluoride urine subsample
(OR, 95% CI)
Adjusted‡ estimates for fluoride urine subsample
(OR, 95% CI)
(n=1466)
Unadjusted† estimates for fluoride urine subsample
(OR, 95% CI)
Adjusted‡ estimates for fluoride urine subsample
(OR, 95% CI)
(n=1570)
Unadjusted† estimates for fluoride tap water subsample
(OR, 95% CI)
Adjusted‡ estimates for fluoride tap water subsample
(OR, 95% CI)
(n=1564)
Urinary fluoride (μmol/L) (cont)0.98 (0.94 to 1.03)0.98 (0.95 to 1.02)1.00 (0.99 to 1.02)1.00 (0.99 to 1.01)
Fluoride concentration of tap water (mg/L) (cont)0.92 (0.22 to 3.94)0.98 (0.28 to 3.45)
Sex (ref: male)6.36* (1.52 to 26.68)6.31* (1.29 to 30.89)4.09* (1.27 to 19.52)4.20* (0.90 to 19.53)4.00* (1.02 to 15.72)4.13* (0.94 to 18.21)
Age (years) (cont)1.04** (1.02 to 1.07)1.05** (1.02 to 1.08)1.05** (1.03 to 1.08)1.06** (1.03 to 1.09)1.05** (1.03 to 1.08)1.06** (1.03 to 1.09)
Household income adequacy (ref: lower and middle income)0.95 (0.39 to 2.35)1.09 (0.29 to 4.07)0.78 (0.23 to 2.61)1.23 (0.30 to 5.03)0.77 (0.22 to 2.64)1.20 (0.30 to 4.83)
Highest attained education in the household
(ref: less than bachelor’s degree)
1.67 (0.84 to 3.28)2.03 (0.81 to 5.10)0.40*** (0.15 to 1.10)0.37*** (0.11 to 1.22)0.41*** (0.15 to 1.11)0.38 (0.12 to 1.26)
  • †Column contains bivariate associations between predictor variable and the outcome (self-reported diagnosis of a thyroid condition).

  • ‡Column contains associations from single model containing all predictor variables (age, sex, household income adequacy and highest attained education in the household).

  • *p<0.05, **p<0.01, ***p<0.1.

  • Note: these models were rerun using creatinine-adjusted urinary fluoride (μmol/mmol) and no significant observations were detected (data not shown).

  • CHMS, Canadian Health Measures Survey; RRR, relative risk ratio; TSH, thyroid-stimulating hormone.