Table 4.

Association between maternal PFOA serum concentrations and duration of breastfeeding (per month), stratified by level of ongoing maternal PFOA uptake.^a

None (background exposure only)			Low			Medium			High
n	Percent changeb (95% CI)	p‑Value	n	Percent changeb (95% CI)	p‑Value	n	Percent changeb (95% CI)	p‑Value	n	Percent changeb (95% CI)	p‑Value
107	–7 (–11, –2)	0.006	299	–4 (–6, –3)	0.000	136	–2 (–5, 1)	0.258	91	–3 (–7, 1)	0.134
aEstimated as the average modeled exposure from the date of the index infant’s birth to the date of the 2005–2006 survey. bEstimates were based on models of maternal lnPFAA concentrations with duration of breastfeeding (per month) as a continuous variable, adjusted for parity (0, 1, 2, > 2), maternal age (categorical in 5-year intervals), infant´s age (categorical in 6-month intervals), and water district.