Table 4

Sensitivity analysis of the association between PFAAs and self-report memory impairment for a doubling PFAA concentration, by quintiles of PFAAs and in ordinal regression on participants aged 65 years and older (n=7,097) and using any memory impairment as outcome measure (n=21 024)

Range (ng/ml)OR (95% CI)* N=7097 restricted to those aged 65+†Range (ng/ml)OR (95% CI)*N=21024 any memory impairment‡
PFOS0.95 (0.90 to 1.00)0.96 (0.94 to 0.99)
Ordinal regression0.98 (0.94 to 1.03)
 1st quintile0.25–15.3Ref.0.25–14.4Ref.
 2nd quintile15.4–22.00.99 (0.83 to 1.20)14.5–20.40.96 (0.88 to 1.05)
 3rd quintile22.1–28.90.95 (0.79 to 1.14)20.5–27.10.90 (0.82 to 0.98)
 4th quintile29.0–4.00.97 (0.81 to 1.16)27.2–37.20.94 (0.86 to 1.03)
 5th quintile40.1–759.20.84 (0.70 to 1.01)37.3–759.20.93 (0.85 to 1.02)
Trend0.0790.121
PFOA0.99 (0.97 to 1.03)0.97 (0.96 to 0.99)
Ordinal regression1.00 (0.97 to 1.03)
 1st quintile0.25–15.0Ref.0.25–14.0Ref.
 2nd quintile15.1–29.60.91 (0.75 to 1.09)14.1–27.00.90 (0.82 to 0.98)
 3rd quintile29.7–56.80.90 (0.75 to 1.08)27.1–53.80.86 (0.79 to 0.94)
 4th quintile56.9–123.00.84 (0.70 to 1.01)53.9–118.10.87 (0.79 to 0.95)
 5th quintile123.1–5994.80.99 (0.83 to 1.19)118.3–22,4120.85 (0.78 to 0.93)
Trend0.680<0.001
PFNA0.95 (0.87 to 1.02)0.98 (0.95 to 1.02)
Ordinal regression0.99 (0.93 to 1.07)
 1st quintile0.25–0.8Ref.0.25–0.90Ref.
 2nd quintile0.9–1.10.88 (0.73 to 1.06)1.0–1.20.89 (0.82 to 0.97)
 3rd quintile1.2–1.40.81 (0.67 to 0.98)1.3–1.40.94(0.85 to 1.04)
 4th quintile1.5–1.80.82 (0.68 to 0.99)1.5–1.90.92 (0.85 to 1.01)
 5th quintile1.9–11.70.88 (0.73 to 1.07)2.0–28.60.94 (0.86 to 1.03)
Trend0.1770.493
PFHxS0.96 (0.91 to 1.01)0.97 (0.94 to 0.99)
Ordinal regression0.98 (0.93 to 1.02)
 1st quintile0.25–1.9Ref.0.25 to 1.7Ref.
 2nd quintile2.0–2.80.98 (0.82 to 1.18)1.8 to 2.60.98 (0.90 to 1.07)
 3rd quintile2.9–3.90.95 (0.79 to 1.15)2.7 to 3.61.03 (0.94 to 1.13)
 4th quintile4.0–6.00.98 (0.82 to 1.17)3.7 to 5.60.96 (0.87 to 1.04)
 5th quintile6.1–232.60.86 (0.71 to 1.03)5.7 to 232.60.89 (0.81 to 0.97)
Trend0.1390.010
  • *Model 2 includes age (1-year age bands), ethnicity, gender, and school level (categorical), household income (categorical), physical activity, alcohol consumption (categorical, none/<1drink/month, <1 drink/week, few drinks/week, 1–3 drinks/day, >3 drinks/day, undetermined) and cigarette smoking (categorical, never, former, <10 cigarette/day, 12–20 cigarette/day, 20+ cigarette/day).

  • †Sensitivity analysis including participants aged 65 years or older only (N=7097).

  • ‡Sensitivity analysis using a more restrictive definition of memory impairment (those reporting frequent episode of short-term memory loss only, cases=1115).

  • PFAA, perfluoroalkyl acids; PFHxS, perfluorohexane sulfonate; PFNA, perfluorononanoic acid; PFOA, perfluorooctanate; PFOS, perfuorooctane sulfonate.