Table 1. Demographic Characteristics and Exposure Outcomes for Mother-Child Pairs With MUFSG (n = 512) and Fluoride Intake Data (n = 400) by Fluoridated and Nonfluoridated Statusa.
| Variableb | No. (%) | ||
|---|---|---|---|
| MUFSG Sample (n = 512)c | Maternal-Child Pairs With Fluoride Intake, IQ, and Complete Covariate Data (n = 400) | ||
| Nonfluoridated (n = 238) | Fluoridated (n = 162) | ||
| Mothers | |||
| Age of mother at enrollment, mean (SD), y | 32.33 (5.07) | 32.61 (4.90) | 32.52 (4.03) |
| Prepregnancy BMI, mean (SD) | 25.19 (6.02) | 25.19 (6.35) | 24.33 (5.10) |
| Married or common law | 497 (97) | 225 (95) | 159 (98) |
| Born in Canada | 426 (83) | 187 (79) | 131 (81) |
| White | 463 (90) | 209 (88) | 146 (90) |
| Maternal education | |||
| Trade school diploma/high school | 162 (32) | 80 (34) | 38 (24) |
| Bachelor’s degree or higher | 350 (68) | 158 (66) | 124 (76) |
| Employed at time of pregnancy | 452 (88) | 205 (86) | 149 (92) |
| Net income household >$70 000 CAD | 364 (71) | 162 (68) | 115 (71) |
| HOME total score, mean (SD) | 47.32 (4.32) | 47.28 (4.48) | 48.14 (3.90) |
| Smoked in trimester 1 | 12 (2) | 7 (3) | 2 (1) |
| Secondhand smoke in the home | 18 (4) | 9 (4) | 2 (1) |
| Alcohol consumption, alcoholic drink/mo | |||
| None | 425 (83) | 192 (81) | 136 (84) |
| <1 | 41 (8) | 23 (10) | 11 (7) |
| ≥1 | 46 (9) | 23 (10) | 15 (9) |
| Parity (first birth) | 233 (46) | 119 (50) | 71 (44) |
| Children | |||
| Female | 264 (52) | 118 (50) | 83 (51) |
| Age at testing, mean (SD), y | 3.42 (0.32) | 3.36 (0.31) | 3.49 (0.29) |
| Gestation, mean (SD), wk | 39.12 (1.57) | 39.19 (1.47) | 39.17 (1.81) |
| Birth weight, mean (SD), kg | 3.47 (0.49) | 3.48 (0.48) | 3.47 (0.53) |
| FSIQ | 107.16 (13.26) | 108.07 (13.31) | 108.21 (13.72) |
| Boysd | 104.61 (14.09) | 106.31 (13.60) | 104.78 (14.71) |
| Girlsd | 109.56 (11.96) | 109.86 (12.83) | 111.47 (11.89) |
| Exposure variables | |||
| MUFSG concentration, mg/Le | |||
| No. | 512 | 228 | 141 |
| Mean (SD) | 0.51 (0.36) | 0.40 (0.27) | 0.69 (0.42) |
| Fluoride intake level per day, mg | |||
| No. | 369a | 238 | 162 |
| Mean (SD) | 0.54 (0.44) | 0.30 (0.26) | 0.93 (0.43) |
| Water fluoride concentration, mg/L | |||
| No. | 369a | 238 | 162 |
| Mean (SD) | 0.31 (0.23) | 0.13 (0.06) | 0.59 (0.08) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CAD, Canadian dollars; FSIQ, Full Scale IQ; HOME, Home Observation for Measurement of the Environment; MUFSG, maternal urinary fluoride adjusted for specific gravity.
SI conversion factor: To convert fluoride to millimoles per liter, multiply by 0.05263.
Owing to missing water treatment plant data and/or MUF data, the samples are distinct with some overlapping participants in both groups (n = 369).
All of the listed variables were tested as potential covariates, as well as the following: paternal variables (age, education, employment status, smoking status, and race/ethnicity); maternal chronic condition during pregnancy and birth country; breastfeeding duration; and time of void and time since last void.
Maternal urinary fluoride (averaged across all 3 trimesters) and corrected for specific gravity.
The FSIQ score has a mean (SD) of 100 (15); US population norms used.
Owing to missing water treatment plant data, the samples in the fluoridated and nonfluoridated regions do not add up to the MUF sample size.