4-Nonylphenol Exposure, Diet, Life Style and Reproductive Health
Date Issued
2012
Date
2012
Author(s)
Chen, Jyh-Larng
Abstract
Preface: Nonylphenol (4-nonylphenol, NP) is the main product of biological decomposition of alkylphenol compounds. It can not be broken down easily by microorganisms in the environment. It has been confirmed by experiments on fish, birds and mammals that NP is an environmental hormone because its structure is similar to estrogen. There are plenty of chances that human may have daily intake of NP through the food chain. However, there are limited studies on human exposure of NP and No study has ever investigated the human reproductive health associated with NP exposure. In this study, we performed a cross-sectional survey to measure the NP levels in urine and blood, and its association with dietary habits, and semen quality in men. We also measured NP levels in maternal and fetal samples of urine and blood to evaluate the vertical partitioning of NP.
Methods and materials: With consent, we recruited a convenient sample of 67 couples at an infertility clinic and 132 pregnant women and their newborns. Urine and blood samples were collected. The urine samples were collected with acid washed containers and creatinine correction, and stored at -20 ℃. Blood and urine samples were purified by solid phase extraction for pretreatment, following high-performance liquid chromatography (HPLC) assay, using fluorescence detector f to determine NP concentrations. Data analyses measured the association between NP levels and diet among 67 couples as well as vertical distribution of NP between 132 mothers and offsprings. We also compared NP levels in urine between women visiting the clinic for infertility treatment and women for general prenatal care. Semen quality was evaluated for 67 men by measuring sperm count (million/ml), and sperm motility (percent) associated with urinary NP levels.
Results: The NP levels in both urine and blood samples were higher in foreign born women than in native women. There were no significant age-specific differences in NP levels in urine and blood samples measured for women with infertility or women for general prenatal care.
We found NP levels in urine and blood samples were not associated with sports, medications, healthy food intake, alcohol consumption, chewing betel nuts, and intake of coffee and tea, etc. However, among women for general prenatal care at the clinic, those with higher intake of whole milk had higher mean blood NP level than those with lower intake (odds ratio = 4.48, 95% confidence interval 2.12 - 9.48). Similar pattern was also observed for the skim milk consumption (odds ratio = 2.32, 95% confidence interval 1.15 - 4.67). All rest of diet factors had no significant association with NP in both urine and blood samples.
The mean urinary NP concentration was significantly higher in pregnant women for the infertility visit than women for the general prenatal care (16.10 + 11.33 vs. 4.32 + 3.81 ng / ml, p < 0.001). The corresponding ratios of median levels were 13.9-fold higher without adjusting creatinine levels and 8.6-fold higher with creatinine being adjusted. Medication and coffee consumption also associated with higher urinary NP in infertility women.
There was no significant differences in urinary NP concentrations between husbands and wifes for infertility treatment (r = 0.31, p < 0.05). The mean NP levels were similar between these husbands and wifes measured by all types of diet and life style.
Among these infertility couples, the mean urinary NP in those with higher whole milk consumption was 4.33-fold (p < 0.05) higher than those with lower consumption. Higher NP concentrations in urine samples were associated with lower sperm concentration (p < 0.001), and less sperm activity (p < 0.001). No other factors were significantly associated with sperm concentration and sperm activity.
Analyzing of the maternal and childhood association in NP measures showed that the chemical was detectable in 82.6% of blood samples and 82.4% of urine samples for mothers. NP was detectable in 67.4% of cord blood samples with the mean about 54.0% of the mean of maternal level. NP was also detectable in 72.4% of urine samples of new borns, with the mean 62.0% of that of mothers (p < 0.001).
Conclusion: The consumption of milk is associated with elevated NP levels intake. The exposure was greater in couples with infertility. Vertical partition of NP from pregnant womam to her fetus is likely. Higher NP exposure is associated with higher risk of impaired sperm quality.
Subjects
nonylphenol
diet
semen quality
reproductive health
risk assessment
SDGs
Type
thesis
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