Table 3.

Hazard ratios of total, osteoporotic, and hip fractures and corresponding 95% CIs by tertiles of urinary fluoride (mg/g creatinine) ($n=\mathrm{4,306}$) and dietary fluoride (mg/d) ($n=\mathrm{4,072}$), respectively.

Categories	Tertiles of urinary fluoride			$p_{\text{Trend}}$	Tertiles of dietary fluoride			$p_{\text{Trend}}$
	1	2	3		1	2	3
$N$	1,436	1,435	1,435		1,358	1,357	1,357
Fluoride exposure {mg/g creatinine or mg/d [median (range)]}	0.68 (0.14–0.88)	1.08 (0.88–1.30)	1.64 (1.30–116.51)		1.38 (0.26–1.74)	2.04 (1.74–2.41)	2.94 (2.41–11.16)
All fractures
Cases	261	267	322		268	272	259
Person-years	12,825	13,232	12,974		12,172	12,505	12,572
Incidence ratea	211 (185–237)	210 (184–235)	254 (227–282)		215 (189–241)	224 (197–251)	228 (199–257)
Age-adjusted HR (95% CI)	1 (Ref)	0.99 (0.83, 1.17)	1.18 (1.01, 1.40)		1 (Ref)	1.03 (0.87, 1.22)	1.03 (0.86, 1.22)
Multivariable-adjusted HR (95% CI)b	1 (Ref)	0.98 (0.82, 1.16)	1.13 (0.95, 1.34)	0.11	1 (Ref)	1.02 (0.86, 1.21)	1.01 (0.85, 1.20)	0.96
Major osteoporotic fractures
Cases	157	161	211		162	169	167
Person-years	13,465	13,817	13,638		12,794	13,124	13,136
Incidence ratea	128 (108–148)	129 (109–149)	167 (145–190)		130 (110–150)	140 (118–161)	153 (129–177)
Age-adjusted HR (95% CI)	1 (Ref)	1.01 (0.81, 1.25)	1.29 (1.05, 1.59)		1 (Ref)	1.06 (0.86, 1.32)	1.12 (0.90, 1.39)
Multivariable-adjusted HR (95% CI)b	1 (Ref)	0.99 (0.79, 1.24)	1.21 (0.98, 1.50)	0.05	1 (Ref)	1.07 (0.86, 1.33)	1.11 (0.89, 1.38)	0.38
Hip fractures
Cases	50	54	83		54	55	65
Person-years	14,127	14,477	14,416		13,464	13,801	13,804
$\text{Incidence rate}$a	43 (31–54)	46 (34–59)	67 (52–81)		42 (31–54)	47 (35–60)	66 (49–82)
Age-adjusted HR (95% CI)	1 (Ref)	1.07 (0.73, 1.58)	1.50 (1.06, 2.13)		1 (Ref)	1.11 (0.76, 1.62)	1.58 (1.10, 2.28)
Multivariable-adjusted $\text{HR}$ (95% CI)b	1 (Ref)	1.12 (0.75, 1.65)	1.50 (1.04, 2.17)	0.02	1 (Ref)	1.12 (0.76, 1.63)	1.59 (1.10, 2.30)	0.01

Note: The total number of participants in the urinary fluoride and dietary fluoride analyses were 4,306 and 4,072, respectively. Two hundred thirty-four women were excluded from the dietary fluoride analyses because of missing dietary fluoride information due either to responding to a shorter version of the FFQ or having missing/inadequate reported dietary intake (energy intake outside 3 SD of the log-transformed mean). For each outcome, women contributed with person-time from the date of clinical examination until the of date of the specific event studied, death, or end of follow-up at 31 December 2017. CI, confidence interval; eGFR, estimated glomerular filtration rate; FFQ, food frequency questionnaire; HR, hazard ratio; Ref, reference; SD, standard deviation.

^aAge-standardized incidence rates per 10,000 person-years.

^bMultivariable-adjusted models were adjusted for age, education, height, total fat mass, lean body mass, parity, smoking status, physical activity, alcohol intake, diabetes, eGFR, tertiles of urinary excretion of calcium (for urinary fluoride) or tertiles of dietary intake of calcium (for dietary fluoride), use of calcium supplements, use of vitamin D supplements, ever use of estrogen, and ever use of corticosteroids. Urinary fluoride models were additionally adjusted for serum Beta-CrossLaps (ng/L).