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Perfluoroalkyl acids and time to pregnancy revisited: An update from the Danish National Birth Cohort.

Bach CC, Liew Z, Bech BH, Nohr EA, Fei C, Bonefeld-Jorgensen EC, Henriksen TB, Olsen J - Environ Health (2015)

Bottom Line: We performed sample-specific and pooled analyses using discrete-time survival analyses to estimate fecundability ratios according to PFOS and PFOA quartiles, adjusted for potential confounders chosen guided by a directed acyclic graph.In the pooled analyses including both parous and iparous women fecundability ratios were 13-22 % lower for the three higher quartiles of PFOS or PFOA compared to the reference quartile.The pooled analyses were driven by the larger old sample, but we did not corroborate our previous finding of an association between high PFOS and longer TTP in the new sample.

View Article: PubMed Central - PubMed

Affiliation: Perinatal Epidemiology Research Unit, Aarhus University Hospital, Skejby, Denmark. ccbach@clin.au.dk.

ABSTRACT

Background: We previously demonstrated an association between plasma perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) and longer time to pregnancy (TTP) in a sample from the Danish National Birth Cohort (DNBC, 1996-2002). In this study we investigated this association in a new sample from the same cohort.

Methods: Sample 1 consisted of 440 women, and Sample 2 consisted of 1161 women from whom we previously published the associations between PFOS or PFOA and TTP. We performed sample-specific and pooled analyses using discrete-time survival analyses to estimate fecundability ratios according to PFOS and PFOA quartiles, adjusted for potential confounders chosen guided by a directed acyclic graph. We also estimated odds ratios for infertility (TTP > 12 months or infertility treatment) according to PFOS and PFOA by multivariable logistic regression.

Results: In Sample 1 PFOS was not associated with lower fecundability ratios or infertility, and there was a tendency towards longer TTP with increasing PFOA only in parous women. In Sample 2 previously reported associations were again seen. In the pooled analyses including both parous and iparous women fecundability ratios were 13-22 % lower for the three higher quartiles of PFOS or PFOA compared to the reference quartile.

Conclusions: The pooled analyses were driven by the larger old sample, but we did not corroborate our previous finding of an association between high PFOS and longer TTP in the new sample. The tendency towards an association for PFOA and TTP in parous women may be due to reverse causation. Results from the new sample are more in line with the recent literature.

No MeSH data available.


Related in: MedlinePlus

Flowchart of participants in two participant samples from the Danish National Birth Cohort
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Fig1: Flowchart of participants in two participant samples from the Danish National Birth Cohort

Mentions: We studied two samples that were selected independently from the DNBC during 1996-2002 (Fig. 1). The source population for Sample 1 was women who gave birth to a live born singleton, participated in the first telephone interview, and provided a blood sample in the first or second trimester (n = 83,389). From these we randomly selected 550 participants who also served as controls in a case-cohort study [18]. Women who gave birth to boys were oversampled since the studied outcomes of the case-cohort study have unequal sex ratios (offspring sex is unlikely to be related to the investigated association).Fig 1


Perfluoroalkyl acids and time to pregnancy revisited: An update from the Danish National Birth Cohort.

Bach CC, Liew Z, Bech BH, Nohr EA, Fei C, Bonefeld-Jorgensen EC, Henriksen TB, Olsen J - Environ Health (2015)

Flowchart of participants in two participant samples from the Danish National Birth Cohort
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4493954&req=5

Fig1: Flowchart of participants in two participant samples from the Danish National Birth Cohort
Mentions: We studied two samples that were selected independently from the DNBC during 1996-2002 (Fig. 1). The source population for Sample 1 was women who gave birth to a live born singleton, participated in the first telephone interview, and provided a blood sample in the first or second trimester (n = 83,389). From these we randomly selected 550 participants who also served as controls in a case-cohort study [18]. Women who gave birth to boys were oversampled since the studied outcomes of the case-cohort study have unequal sex ratios (offspring sex is unlikely to be related to the investigated association).Fig 1

Bottom Line: We performed sample-specific and pooled analyses using discrete-time survival analyses to estimate fecundability ratios according to PFOS and PFOA quartiles, adjusted for potential confounders chosen guided by a directed acyclic graph.In the pooled analyses including both parous and iparous women fecundability ratios were 13-22 % lower for the three higher quartiles of PFOS or PFOA compared to the reference quartile.The pooled analyses were driven by the larger old sample, but we did not corroborate our previous finding of an association between high PFOS and longer TTP in the new sample.

View Article: PubMed Central - PubMed

Affiliation: Perinatal Epidemiology Research Unit, Aarhus University Hospital, Skejby, Denmark. ccbach@clin.au.dk.

ABSTRACT

Background: We previously demonstrated an association between plasma perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) and longer time to pregnancy (TTP) in a sample from the Danish National Birth Cohort (DNBC, 1996-2002). In this study we investigated this association in a new sample from the same cohort.

Methods: Sample 1 consisted of 440 women, and Sample 2 consisted of 1161 women from whom we previously published the associations between PFOS or PFOA and TTP. We performed sample-specific and pooled analyses using discrete-time survival analyses to estimate fecundability ratios according to PFOS and PFOA quartiles, adjusted for potential confounders chosen guided by a directed acyclic graph. We also estimated odds ratios for infertility (TTP > 12 months or infertility treatment) according to PFOS and PFOA by multivariable logistic regression.

Results: In Sample 1 PFOS was not associated with lower fecundability ratios or infertility, and there was a tendency towards longer TTP with increasing PFOA only in parous women. In Sample 2 previously reported associations were again seen. In the pooled analyses including both parous and iparous women fecundability ratios were 13-22 % lower for the three higher quartiles of PFOS or PFOA compared to the reference quartile.

Conclusions: The pooled analyses were driven by the larger old sample, but we did not corroborate our previous finding of an association between high PFOS and longer TTP in the new sample. The tendency towards an association for PFOA and TTP in parous women may be due to reverse causation. Results from the new sample are more in line with the recent literature.

No MeSH data available.


Related in: MedlinePlus