Table 1.
Descriptive statistics for Cycles 2 and 3 of the Canadian Health Measures Survey (weighted and bootstrapped). The sample sizes presented at the top of the table reflect the full available sample; however, in some cases, the sample sizes in the cells are lower due age exclusions (primary reason) and missing data (less than 5% in all cases). See notes below
| Cycle 2—full sample (n=6395) |
Cycle 2— fluoride urine subsample (n=2530) |
Cycle 2— constrained urine fluoride subsample* (n=649) |
Cycle 3—full sample (n=5785) |
Cycle 3—fluoride urine subsample (n=2671) |
Cycle 3—constrained urine fluoride subsample† (n=852) |
|
| Predictors | ||||||
| Urinary fluoride (μmol/L) | – | 33.55 (95% CI 30.71 to 36.39) | 40.46 (95% CI 34.45 to 46.46) | – | 29.81 (95% CI 26.51 to 33.10) | 35.15 (95% CI 28.10 to 42.20) |
| Fluoride concentration of tap water (mg/L) | – | – | – | – | 0.22 (95% CI 0.15 to 0.30) | 0.35 (95% CI 0.21 to 0.49) |
| Outcomes | ||||||
| Self-reported thyroid condition diagnosis‡ (yes) | 5.67% (95% CI 4.72 to 6.62) | 3.43% (95% CI 1.77 to 5.08) | 5.51% (95% CI 1.29 to 9.74) | 6.85% (95% CI 4.87 to 8.83) | 5.62% (95% CI 3.64 to 7.60) | 6.02% (95% CI 3.09 to 8.95) |
| Thyroid-stimulating hormone level (low/normal/high) | – | – | – | 3.33% (95% CI 1.93 to 4.73) | 2.83% (95% CI 1.43 to 4.23) | 4.14% (95% CI 1.83 to 6.44) |
| – | – | – | 93.15% (95% CI 91.20 to 95.09) | 94.95% (95% CI 93.01 to 96.90) | 93.34% (95% CI 88.72 to 97.96) | |
| – | – | – | 3.52% (95% CI 2.64 to 4.41) | 2.22% (95% CI 1.33 to 3.10) | 2.52% (95% CI 0.00 to 5.47) | |
| Hypothyroidism (yes) | – | – | – | 0.49% (95% CI 0.00 to 1.60) | 0.80% (95% CI 0.00 to 1.90) | Not releasable |
| Covariates | ||||||
| Sex (females) | 50.06% | 44.91% (95% CI 40.82 to 49.00) | 45.30% (95% CI 36.79 to 53.80) | 50.06% | 48.70% | 48.63% (95% CI 42.07 to 55.19) |
| Age (years) (cont) | 38.57 (95% CI 38.35 to 38.80) | 32.55 (95% CI 31.32 to 33.77) | 35.12 (95% CI 32.26 to 37.97) | 39.05 (95% CI 38.40 to 39.70) | 35.69 (95% CI 35.04 to 36.34) | 35.33 (95% CI 33.73 to 36.93) |
| Household Income adequacy‡ (lower and middle income) | 49.54% (95% CI 43.88 to 55.19) | 47.60% (95% CI 42.76 to 52.44) | 44.02% (95% CI 36.14 to 51.90) | 51.79% (95% CI 42.76 to 60.82) | 45.34% (95% CI 36.31 to 54.37) | 42.75% (95% CI 27.72 to 57.78) |
| Highest attained education in the household (less than bachelor’s degree) | 63.97% (95% CI 57.32 to 70.62) | 64.97% (95% CI 56.98 to 72.96) | 64.26% (95% CI 52.25 to 76.27) | 59.26% (95% CI 48.75 to 69.77) | 54.83% (95% CI 44.31 to 65.34) | 56.46% (95% CI 41.63 to 71.28) |
| Variables related to sources of fluoride exposure | ||||||
| Respondent from a fluoridated collection site (yes) | 54.92% (95% CI 40.00 to 69.87) | 54.96% (95% CI 40.26 to 69.67) | – | 54.54% (95% CI 28.43 to 80.66) | 53.73% (95% CI 27.62 to 79.85) | – |
| Length of time in current home (≥3 years) | 71.15% (95% CI 68.50 to 73.80) |
70.69% (95% CI 67.55 to 73.83) | – | – | – | – |
| Primary source of drinking water (tap water) | 65.56% (95% CI 62.41 to 68.72) | 63.48% (95% CI 59.48 to 67.48) | – | – | – | -- |
| Uses fluoride-containing dental products at home (yes) | – | – | – | 84.21% (95% CI 80.55 to 87.87) | 84.34% (95% CI 80.68 to 88.00) | – |
| Ever received fluoride-treatments at the dentist (yes) | – | – | – | 80.95% (95% CI 78.03 to 83.86) | 81.29% (95% CI 78.37 to 84.20) | – |
*For Cycle 2, the constrained fluoride urine subsample refers to respondents who: 1) attended a fluoridated data collection site, 2) identified tap water was their primary source of drinking water at home or away from home and, 3) lived in their current home for three or more years.
†For Cycle 3, the constrained fluoride urine subsample refers to respondents who: 1) attended a fluoridated data collection site, 2) reported using fluoride-containing dental products at home and, 3) reported ever receiving fluoride treatments at the dentist.
‡Survey question regarding self-reported diagnosis of a thyroid condition was only asked to respondents age 12 and older
§Only 71% and 77% of respondents reported their total household income for Cycle 2 and Cycle 3 of the CHMS, respectively. Accordingly. Statistics Canada developed a regression model to impute total household income for all respondents for both Cycles.