Table 3.

HRs (95% CIs) for PFAS mixture/PFOA/PFOS exposure and mortality risk in the NHANES follow-up study from 1999–2014 to 31 December 2015 ($n=\mathrm{11,747}$).

Categories	All-cause mortality			Heart disease mortality			Cancer mortality
	Deaths/observations ($n/N$)	Unadjusted HR	Adjusted HR	Deaths/observations ($n/N$)	Unadjusted HR	Adjusted HR	Deaths/observations ($n/N$)	Unadjusted HR	Adjusted HR
Total PFAS (exposure)a
Low	313/3,913	Ref	Ref	81/3,913	Ref	Ref	43/3,913	Ref	Ref
Medium	532/5,491	1.15 (0.90, 1.45)	1.02 (0.78, 1.33)	184/5,491	1.38 (0.98, 1.87)	1.14 (0.76, 1.74)	135/5,491	1.58 (1.05, 2.46)	1.31 (0.83, 2.16)
High	406/2,343	1.62 (1.33, 1.97)	1.38 (1.07, 1.80)	107/2,343	1.81 (1.20, 2.62)	1.58 (1.05, 2.51)	70/2,343	2.05 (1.27, 3.19)	1.70 (1.08, 2.84)
PFOA [tertile (ng/mL)]b
First ($<2.4$)	322/3,913	Ref	Ref	100/3,913	Ref	Ref	59/3,913	Ref	Ref
Second ($2.4–4.3$)	418/3,842	1.29 (1.06, 1.58)	1.10 (0.86, 1.41)	128/3,842	1.28 (0.92, 1.79)	1.13 (0.78, 1.67)	74/3,842	1.10 (0.70, 1.70)	0.99 (0.60, 1.62)
Third ($\ge 4.3$)	511/3,992	1.34 (1.11, 1.61)	1.22 (0.93, 1.58)	144/3,992	1.30 (0.96, 1.83)	1.15 (0.73, 1.73)	115/3,992	1.23 (0.83, 1.83)	1.06 (0.68, 1.71)
PFOS [tertile (ng/mL)]c
First ($<7.9$)	199/3,886	Ref	Ref	62/3,886	Ref	Ref	39/3,886	Ref	Ref
Second ($7.9–17.1$)	372/3,917	1.36 (1.08, 1.70)	1.13 (0.86, 1.44)	129/3,917	1.40 (0.96, 2.05)	1.19 (0.78, 1.80)	79/3,917	1.45 (0.95, 2.25)	1.26 (0.75, 2.06)
Third ($\ge 17.1$)	680/3,944	1.83 (1.50, 2.31)	1.57 (1.22, 2.07)	181/3,944	1.88 (1.34, 2.75)	1.65 (1.09, 2.57)	130/3,944	2.13 (1.41, 3.27)	1.75 (1.10, 2.83)

Note: HRs were estimated using Cox proportional hazards models and were weight adjusted using NHANES-specified sampling weights. Missing data on covariates were processed using the multiple imputation algorithm. Samples with test values below the LOQ were substituted with the value of the LOQ divided by the square root of 2. BMI, body mass index; Ccr, creatinine clearance rate; CI, confidence interval; HR, hazard ratio; LOQ, limit of quantification; NHANES, National Health and Nutrition Examination Survey; PFAS, per- and polyfluoroalkyl substances; PFOA, perfluorooctanoic acid; PFOS, perfluorooctane sulfonic acid; Ref, reference.

^a HRs were adjusted for sex, age, race/ethnicity, smoking status, alcohol intake, physical activity, hypertension, healthy eating index, BMI, Ccr, serum total cholesterol, and serum cotinine.

^b HRs were adjusted for PFAS excluding PFOA (categorized into three groups based on k-means algorithm), sex, age, race/ethnicity, smoking status, alcohol intake, physical activities, hypertension, diabetes, healthy eating index, Ccr, serum total cholesterol, and serum cotinine.

^c HRs were adjusted for PFAS excluding PFOS (categorized into three groups based on k-means algorithm), sex, age, race/ethnicity, education, smoking status, physical activity, hypertension, healthy eating index, Ccr, serum total cholesterol, and serum cotinine.