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Fontanesi L, Verrocchio MC, D'Ettorre M, Prete G, Ceravolo F, Marchetti D. The impact of catastrophic events on the sex ratio at birth: A systematic review. Am J Hum Biol 2024; 36:e24003. [PMID: 37916952 DOI: 10.1002/ajhb.24003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/26/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023] Open
Abstract
OBJECTIVE The impact of maternal stress on birth outcomes is well established in the scientific research. The sex ratio at birth (SRB), namely the ratio of male to female live births, shows significant alteration when mothers experience acute stress conditions, as proposed by the Trivers-Willard Hypothesis. We aimed to synthetize the literature on the relationship between two exogenous and catastrophic stressful events (natural disasters and epidemics) and SRB. METHODS A systematic search was run in Scopus, PubMed, Web of Science, and Cochrane Library, until March 9, 2023. The search produced 1336 articles and 25 articles met the inclusion criteria. We found seven case-control studies and 18 observational studies. Most of studies investigated the impact of earthquakes and other natural disasters. Only seven studies examined the effect of epidemics or pandemics. RESULTS The results of the studies seem inconsistent, as 16 studies found a decline in SRB, three found a rise, four did not record any change and two studies gave contradictory results. The period and population analyzed, the source of information, the method of variance analysis in the SRB, and the failure to assess confounding variables may have influenced the incongruence of the results. CONCLUSION Our findings contribute to improve the knowledge about the relationship between socio-ecological factors and SRB. Future studies should investigate the mechanisms by which this relationship impacts public health, in particular the health of pregnant women and their newborn, through an accurate and consistent methodology that also includes confounding factors.
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Affiliation(s)
- Lilybeth Fontanesi
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Maria Cristina Verrocchio
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Melissa D'Ettorre
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Giulia Prete
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Francesco Ceravolo
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
| | - Daniela Marchetti
- Department of Psychological, Health and Territorial Sciences, G. d'Annunzio University of Chieti-Pescara, Chieti, Italy
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Abrantes-Soares F, Lorigo M, Cairrao E. Effects of BPA substitutes on the prenatal and cardiovascular systems. Crit Rev Toxicol 2022; 52:469-498. [PMID: 36472586 DOI: 10.1080/10408444.2022.2142514] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bisphenol A (BPA) is a ubiquitous chemical compound constantly being released into the environment, making it one of the most persistent endocrine-disrupting chemical (EDC) in nature. This EDC has already been associated with developing various pathologies, such as diabetes, obesity, and cardiovascular, renal, and behavioral complications, among others. Therefore, over the years, BPA has been replaced, gradually, by its analog compounds. However, these compounds are structurally similar to BPA, so, in recent years, questions have been raised concerning their safety for human health. Numerous investigations have been performed to determine the effects BPA substitutes may cause, particularly during pregnancy and prenatal life. On the other hand, studies investigating the association of these compounds with the development of cardiovascular diseases (CVD) have been developed. In this sense, this review summarizes the existing literature on the transgenerational transfer of BPA substitutes and the consequent effects on maternal and offspring health following prenatal exposure. In addition, these compounds' effects on the cardiovascular system and the susceptibility to develop CVD will be presented. Therefore, this review aims to highlight the need to investigate further the safety and benefits, or hazards, associated with replacing BPA with its analogs.
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Affiliation(s)
- Fatima Abrantes-Soares
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Margarida Lorigo
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.,FCS-UBI, Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal
| | - Elisa Cairrao
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal.,FCS-UBI, Faculty of Health Sciences, University of Beira Interior, Covilhã, Portugal
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3
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Morse A, Luke N. Foetal loss and feminine sex ratios at birth in sub-Saharan Africa. POPULATION STUDIES 2021; 75:239-254. [PMID: 33599566 PMCID: PMC8833094 DOI: 10.1080/00324728.2021.1877793] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 09/08/2020] [Indexed: 10/22/2022]
Abstract
A wealth of demographic research has explored the determinants of sex ratios at birth, but few studies have considered the role of foetal loss (spontaneous abortion), in producing feminine sex ratios. One challenge is measuring the occurrence of foetal loss, which is difficult to recognize and report in survey research. This study uses the length of the birth interval as a proxy for foetal loss; foetal loss restarts the clock on time to conception and lengthens the birth interval. We use Demographic and Health Survey data on second births to women in 17 sub-Saharan African countries. Results show that longer second birth intervals are significantly related to lower odds of a male second birth and to feminine sex ratios at birth. These findings suggest that high levels of foetal loss, which could signal underlying poor maternal health in a population, have dramatic effects on the sex ratio at birth.
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Affiliation(s)
- Anne Morse
- Department of Sociology and Criminology, The Pennsylvania State University, State College, PA, U.S
| | - Nancy Luke
- Department of Sociology and Criminology, The Pennsylvania State University, State College, PA, U.S
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4
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Bae J. Effects of Socio-demographic Factors on the Decreasing Trend in the Sex Ratio at Birth in Korea, 1997-2017. J Prev Med Public Health 2020; 53:371-380. [PMID: 33070509 PMCID: PMC7569017 DOI: 10.3961/jpmph.20.282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/21/2020] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES This study investigated the effects of socio-demographic factors on the decreasing trend in the sex ratio at birth from 1997 to 2017 in Korea. METHODS Data from 10 349 602 live births registered with Statistics Korea from 1997 to 2017 were analyzed. The secondary sex ratio (SSR), defined as the ratio of male to female live births, during the study period (1997-1999 [phase I], 2000-2002 [phase II], 2003-2005 [phase III], 2006-2008 [phase IV], 2009-2011 [phase V], 2012-2014 [phase VI], and 2015-2017 [phase VII]) was calculated according to selected socio-demographic factors, such as parental age, education, occupation, and birth order. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals for a male birth after adjusting for potential confounders. RESULTS The SSR gradually decreased from 1.10 (in 1998-2000 and 2002) to 1.05 (in 2013-2016). While a decreasing trend in the SSR was not noted among first births, male-biased sex ratios were prominent among third and higher-order births, for which the highest SSR was 1.46 in 1998. Higher birth order was significantly associated with an excess of male births in phases I-VI (≥third vs. first, OR range, 1.03 to 1.35). Advanced maternal age was significantly associated with an excess of female births in phases II, III, and V (≥40 vs. 20-24 years, OR range, 0.92 to 0.95). CONCLUSIONS This study demonstrated that advanced maternal age and reduction of the artificially-biased SSR among third and higher-order births may partially explain the decreasing trend in the SSR from 1997 to 2017 in Korea.
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Affiliation(s)
- Jisuk Bae
- Department of Preventive Medicine, Daegu Catholic University School of Medicine, Daegu, Korea
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5
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Abstract
INTRODUCTION The sex ratio at birth has been studied for decades. A systematic review of the factors that influence this has never been performed. This study conducted a systematic search of this topic. METHODS A scoping review of the literature was initially carried out in January 2012 and this was formally updated for contemporaneity in December 2017. A systematic search of the literature subsequently followed in May 2019 and was conducted based on PRISMA statement's flow diagram. The search was applied across five databases: Cumulative Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, PubMed, The Cochrane Library and Web of Science and was restricted to January 1, 1990 to May 31, 2019. The systematic review stopped at screening stage of the PRISMA. A narrative approach was adopted to report study findings. RESULTS 494 studies were included. Ten factors were identified from the literature as having an influence on M/F, with stress and sex-selective termination being the most predominant. Additional factors included the hormonal theory, geographical trends, coital rates, radiation, secular trends, seasonality and theoretical modeling. DISCUSSION Future studies addressing M/F should adopt similar methodologies in order to provide the possibility of comparison between findings and a more formal form of systematic review.
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Affiliation(s)
- Lorna West
- Medicines Use Research Group, Department of Clinical Pharmacology and Therapeutics, University of Malta, Msida, Malta.
| | - Victor Grech
- Department of Paediatrics, Medical School, Mater Dei Hospital, Malta.
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6
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Lavoie MD, Tedeschi JN, Garcia‐Gonzalez F, Firman RC. Exposure to male-dominated environments during development influences sperm sex ratios at sexual maturity. Evol Lett 2019; 3:392-402. [PMID: 31388448 PMCID: PMC6675145 DOI: 10.1002/evl3.123] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/15/2019] [Accepted: 05/21/2019] [Indexed: 11/18/2022] Open
Abstract
Different stages during development are important when it comes to phenotypic adjustments in response to external stimuli. Critical stages in mammals are the prenatal phase, where embryos are exposed to a milieu of sex steroid hormones, and the early-postnatal phase, where littermates interact and experience their incipient social environment. Further, the postmaternal environment will influence the development of traits that are linked to reproductive success in adulthood. Accumulated evidence of male-driven sex allocation establishes the currently untested hypothesis that the sperm sex ratio is a plastic trait that can be mediated to align with prevailing social conditions. Here, we used natural variation in the maternal environment and experimentally manipulated the postmaternal environment to identify the importance of these developmental phases on sperm sex ratio adjustments in wild house mice (Mus musculus domesticus). We found that male density in both environments was predictive of sperm sex ratios at sexual maturity: males from more male-biased litters and males maturing under high male density produced elevated levels of Y-chromosome-bearing sperm. Our findings indicate that the sperm sex ratio is a variable phenotypic trait that responds to the external environment, and highlight the potential that these adjustments function as a mechanism of male-driven sex allocation.
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Affiliation(s)
- Misha D. Lavoie
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
| | - Jamie N. Tedeschi
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
| | - Francisco Garcia‐Gonzalez
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
- Estacion Biológica de DoñanaCSICSevillaSpain
| | - Renée C. Firman
- School of Biological Sciences (M092), Centre for Evolutionary BiologyThe University of Western AustraliaCrawleyWA6009Australia
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7
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Dobrzyńska MM, Gajowik A, Jankowska-Steifer EA, Radzikowska J, Tyrkiel EJ. Reproductive and developmental F1 toxicity following exposure of pubescent F0 male mice to bisphenol A alone and in a combination with X-rays irradiation. Toxicology 2018; 410:142-151. [PMID: 30321649 DOI: 10.1016/j.tox.2018.10.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 09/11/2018] [Accepted: 10/11/2018] [Indexed: 10/28/2022]
Abstract
Exposure to environmental toxicants may affect reproduction and development of subsequent generations. This study was aimed at determining the male-mediated F1 effects induced following 8-weeks of subchronic exposure of F0 male mice to bisphenol A (BPA) alone and in a combination with X-rays irradiation (IR) started during their puberty. 4.5 weeks old F0 male mice were exposed to BPA dissolved in ethyl alcohol and diluted in drinking water at the following doses: 5 mg/kg bw, 10 mg/kg bw, 20 mg/kg bw or irradiated with X-rays (0.05 Gy) or exposed to a combination of low doses of both agents (0.05 Gy + 5 mg/kg bw BPA). Immediately after the end of the 8 weeks exposure F0 males were caged with two unexposed females each. Three quarters of the mated females from each group were sacrificed 1 day before expected parturition for examination of prenatal development of the offspring. The remainder of the females from each group were allowed to deliver and rear litters. Pups of exposed males were monitored for postnatal development for 8 weeks. At 8-9 weeks of age 6-8 males from each group of F1 generation were sacrificed to determine sperm count and quality. The current results, compared to the earlier results, showed that exposure of pubescent males to BPA alone or in combination with irradiation may be more damaging to their offspring than the exposure of adult males. The exposure of pubescent males to BPA alone and in combination with irradiation significantly increased the frequency of abnormal skeletons of surviving fetuses, increased the percent of mortality of pups in the F1 generation, reduced the sperm motility of F1 males and may induce obesity. Additionally, the combined BPA and irradiation exposure reduced the number of total and live implantations, whereas the exposure to BPA alone disturbed the male:female sex ratio. The above results may be caused by genetic or by epigenetic mechanisms. Limitation of use of products including BPA, especially by children and teenagers, is strongly recommended.
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Affiliation(s)
- Małgorzata M Dobrzyńska
- Department of Radiation Hygiene and Radiobiology, National Institute of Public Health - National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland.
| | - Aneta Gajowik
- Department of Radiation Hygiene and Radiobiology, National Institute of Public Health - National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland
| | - Ewa A Jankowska-Steifer
- Department of Histology and Embryology, Medical University of Warsaw, 5 Chałubińskiego Street, 02-004, Warsaw, Poland
| | - Joanna Radzikowska
- Department of Radiation Hygiene and Radiobiology, National Institute of Public Health - National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland
| | - Ewa J Tyrkiel
- Department of Radiation Hygiene and Radiobiology, National Institute of Public Health - National Institute of Hygiene, 24 Chocimska Street, 00-791, Warsaw, Poland
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8
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Wan Y, Huo W, Xu S, Zheng T, Zhang B, Li Y, Zhou A, Zhang Y, Hu J, Zhu Y, Chen Z, Lu S, Wu C, Jiang M, Jiang Y, Liu H, Yang X, Xia W. Relationship between maternal exposure to bisphenol S and pregnancy duration. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 238:717-724. [PMID: 29621731 DOI: 10.1016/j.envpol.2018.03.057] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 03/16/2018] [Accepted: 03/16/2018] [Indexed: 05/21/2023]
Abstract
Bisphenol S (BPS) has been progressively used due to the potential safety problems of bisphenol A (BPA). Thus Human studies are needed to investigate the developmental effects of BPS. In this study, the impact of maternal BPS exposure on birth outcomes was evaluated with linear and logistic regression models. BPS was analyzed in spot urine samples collected from 985 pregnant women at admission to labor. It was found in 93.7% of the urine samples with the specific gravity adjusted geometric mean concentration of 0.17 μg/L. One ln-unit increase in urinary BPS was associated with a 0.72-day increase in pregnancy duration (95% CI: 0.34, 1.09). When stratified by fetal sex, each ln-unit increase in maternal urinary BPS was significantly correlated with increased gestational age [adjusted β = 1.02, 95% confidence intervals (CI): 0.47, 1.57] and increased odds of late term birth [adjusted odds ratio = 1.29, 95% CI: 1.00, 1.67] for girls, but not significantly for boys. Including maternal urinary BPA and BPS in one model did not change the results. Associations of BPS with birth weight or length were not observed. This is the first report about BPS exposure for pregnant women from China. Higher maternal urinary BPS concentrations were associated with increased gestational age, suggesting maternal BPS exposure may interfere with pregnancy duration. The findings require replication but reveal the probable risks posed by the developmental BPS exposure.
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Affiliation(s)
- Yanjian Wan
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China; Institute of Environmental Health, Wuhan Center for Disease Control and Prevention, Wuhan, Hubei, PR China
| | - Wenqian Huo
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China; Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, Henan, People's Republic of China
| | - Shunqing Xu
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Tongzhang Zheng
- Department of Environmental Health Sciences, Brown School of Public Health, Providence, RI 02903, USA
| | - Bin Zhang
- Women and Children Medical and Healthcare Center of Wuhan, Wuhan, Hubei, People's Republic of China
| | - Yuanyuan Li
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Aifen Zhou
- Women and Children Medical and Healthcare Center of Wuhan, Wuhan, Hubei, People's Republic of China
| | - Yiming Zhang
- Women and Children Medical and Healthcare Center of Wuhan, Wuhan, Hubei, People's Republic of China
| | - Jie Hu
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Yingshuang Zhu
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Zhong Chen
- Women and Children Medical and Healthcare Center of Wuhan, Wuhan, Hubei, People's Republic of China
| | - Shi Lu
- Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Chuansha Wu
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Minmin Jiang
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Yangqian Jiang
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Hongxiu Liu
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xueyu Yang
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Wei Xia
- Key Laboratory of Environment and Health (HUST), Ministry of Education & Ministry of Environmental Protection, State Key Laboratory of Environmental Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China.
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9
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Bae J, Kim S, Chen Z, Eisenberg ML, Buck Louis GM. Human semen quality and the secondary sex ratio. Asian J Androl 2018; 19:374-381. [PMID: 26975484 PMCID: PMC5427797 DOI: 10.4103/1008-682x.173445] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the association between semen quality and the secondary sex ratio (SSR), defined as the ratio of male to female live births. Our study cohort comprised 227 male partners who were enrolled prior to conception in Michigan and Texas between 2005 and 2009, and prospectively followed through delivery of a singleton birth. The male partners provided a baseline and a follow-up semen sample a month apart. Semen analysis was conducted to assess 27 parameters including five general characteristics, six sperm head measures, 14 morphology measures, and two sperm chromatin stability assay measures. Modified Poisson regression models with a robust error variance were used to estimate the relative risk (RR) and 95% confidence interval (95% CI) of a male birth for each semen parameter, after adjusting for potential confounders. Of the 27 semen parameters, only the percentage of bicephalic sperm was significantly associated with the SSR (2ndvs 1st quartile, RR, 0.65, 95% CI, 0.45–0.95, P = 0.03; 4thvs 1st quartile, RR, 0.61, 95% CI, 0.38–1.00, P < 0.05 before rounding to two decimal places), suggestive of a higher percentage of bicephalic sperm being associated with an excess of female births. Given the exploratory design of the present study, this preconception cohort study suggests no clear signal that human semen quality is associated with offspring sex determination.
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Affiliation(s)
- Jisuk Bae
- Department of Preventive Medicine, Catholic University of Daegu School of Medicine, Daegu 42472, Korea.,Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
| | - Sungduk Kim
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
| | - Zhen Chen
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
| | - Michael L Eisenberg
- Department of Urology, Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA 94305-5118, USA
| | - Germaine M Buck Louis
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Rockville, MD 20852, USA
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10
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Bae J, Kim S, Barr DB, Buck Louis GM. Maternal and paternal serum concentrations of persistent organic pollutants and the secondary sex ratio: A population-based preconception cohort study. ENVIRONMENTAL RESEARCH 2018; 161:9-16. [PMID: 29096317 PMCID: PMC5747985 DOI: 10.1016/j.envres.2017.10.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 10/25/2017] [Accepted: 10/26/2017] [Indexed: 05/24/2023]
Abstract
Recent declines in the secondary sex ratio (SSR), defined as the ratio of males to females at birth, in some industrialized countries may be attributed to exposure to environmental toxicants such as persistent organic pollutants (POPs). This study aimed to evaluate the association of couples' preconception exposure to POPs with the SSR. The study cohort comprised 235 couples who were enrolled in the Longitudinal Investigation of Fertility and the Environment (LIFE) Study between 2005 and 2009 prior to conception and prospectively followed through delivery of a singleton birth. Upon enrollment, couples' serum concentrations (ng/g) were measured for 9 organochlorine pesticides, 1 polybrominated biphenyl, 10 polybrominated diphenyl ethers, and 36 polychlorinated biphenyls (PCBs). Birth outcome data including infant sex were collected upon delivery. Modified Poisson regression models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) of a male birth for each chemical. Of the 56 POPs examined, maternal PCB 128 and paternal hexachlorobenzene were significantly associated with a female excess (RRs, 0.75 [95% CI, 0.60-0.94] and 0.81 [95% CI, 0.68-0.97] per 1SD increase in log-transformed serum chemical concentrations, respectively), whereas maternal mirex and paternal PCB 128 and p,p'-dichlorodiphenyldichloroethylene were significantly associated with a male excess (RR range, 1.10-1.22 per 1SD increase in log-transformed serum chemical concentrations). After adjusting for multiple comparisons, only maternal mirex remained significantly associated with the SSR. This exploratory study on multiple classes of POPs demonstrated no conclusive evidence on the association between parental preconception exposure to POPs and the SSR.
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Affiliation(s)
- Jisuk Bae
- Department of Preventive Medicine, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17-gil Nam-gu, Daegu 42472, Republic of Korea.
| | - Sungduk Kim
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B Rockledge Drive, Bethesda, MD 20817, USA; Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, 9609 Medical Center Drive, Bethesda, MD 20892, USA.
| | - Dana Boyd Barr
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322, USA.
| | - Germaine M Buck Louis
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6710B Rockledge Drive, Bethesda, MD 20817, USA.
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11
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Abstract
The human sex ratio (proportion male) at birth (SRB) varies with many variables. Some of this variation has an established proximate cause. For instance, low SRB (more females) at birth are associated with various forms of stressful events or circumstances during or prior to pregnancy. These low SRB are almost certainly mainly caused by maternal-stress-induced male foetal loss. Other types of SRB variation are thought to be caused by hormonal variation in either or both parents around the time of conception. One or other of these two types of proximate cause seems to be responsible for most of the established variation of SRB. This will be illustrated here in respect of some selected forms of SRB variation. It seems likely that a clarification of the hormonal causes of SRB variation will also help explain the striking (apparent) inconsistencies in the results of reported tests of the influential Trivers-Willard hypothesis. It is further proposed that an appreciation of the evidence that parental hormones influence SRB may enhance understanding of several important pathologies (hepatitis B, toxoplasmosis, testicular cancer, prostate cancer and autism).
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Affiliation(s)
- William H James
- The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, United Kingdom.
| | - Victor Grech
- Department of Paediatrics, Mater Dei Hospital Medical School, Malta.
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12
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Bae J, Kim S, Kannan K, Buck Louis GM. Couples' urinary concentrations of benzophenone-type ultraviolet filters and the secondary sex ratio. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 543:28-36. [PMID: 26575635 PMCID: PMC4688162 DOI: 10.1016/j.scitotenv.2015.11.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/16/2015] [Accepted: 11/04/2015] [Indexed: 05/21/2023]
Abstract
The secondary sex ratio (SSR), defined as the ratio of males to females at birth, has been investigated in relation to endocrine disruptors to search for environmental toxicants perturbing human sex selection. Benzophenone (BP)-type ultraviolet (UV) filters, which are used in sunscreens and personal care products, have been reported to exert estrogenic and anti-androgenic activities. This study aimed to evaluate the association between maternal, paternal, and couple urinary concentrations of BP-type UV filters and the SSR, given the absence of previous investigation. The study cohort comprised 220 couples who were enrolled in the Longitudinal Investigation of Fertility and the Environment (LIFE) Study between 2005 and 2009 prior to conception and who had a singleton birth during the follow-up period. Couples' urinary concentrations of five BP-type UV filters (ng/mL) were measured using triple-quadrupole tandem mass spectrometry: 2,4-dihydroxybenzophenone (BP-1), 2,2',4,4'-tetrahydroxybenzophenone (BP-2), 2-hydroxy-4-methoxybenzophenone (BP-3), 2,2'-dihydroxy-4-methoxybenzophenone (BP-8), and 4-hydroxybenzophenone (4-OH-BP). Modified Poisson regression models were used to estimate the relative risks (RRs) of a male birth for each BP-type UV filter, after adjusting for potential confounders. When maternal and paternal urinary BP-type UV filter concentrations were modeled jointly, both maternal BP-2 (2nd vs 1st tertile, RR, 0.62, 95% confidence interval [CI], 0.43-0.91) and paternal BP-2 (3rd vs 1st tertile, RR, 0.67, 95% CI, 0.45-0.99; p-trend, 0.04) were significantly associated with an excess of female births. Contrarily, maternal 4-OH-BP was significantly associated with an excess of male births (2nd vs 1st tertile, RR, 1.87, 95% CI, 1.27-2.74; 3rd vs 1st tertile, RR, 1.80, 95% CI, 1.13-2.87; p-trend, 0.02). Our findings provide the first evidence suggesting that BP-type UV filters may affect the SSR. However, future corroboration is needed, given the exploratory design of this study.
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Affiliation(s)
- Jisuk Bae
- Department of Preventive Medicine, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17-gil, Nam-gu, Daegu 42472, Republic of Korea; Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA.
| | - Sungduk Kim
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA.
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA; Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA.
| | - Germaine M Buck Louis
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA.
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Abstract
INTRODUCTION In humans in the absence of significant stress the sex ratio at birth [males/(males+females)] is in favor of more male than female live births. METHODS This study sought to determine the influence of the 2010 Fédération Internationale de Football Association (FIFA) World Cup in South Africa on the sex ratio at birth in that country specifically 9months afterwards. Publicly available data from Statistics South Africa was utilized detailing recorded live births. Analysis was carried out by Chi-squared tests. RESULTS February and March 2011 about 9months after the World Cup, had the highest observed sex ratio at birth (relatively more male births) of 0.5063 for the period 2003 to 2012. The observed sex ratio at birth in the considered two months of 2011 was 0.63% (p=0.02) greater than the sex ratio at birth for corresponding periods from 2008 to 2012. The increase noted in 2011 corresponds to more than 1000 extra male births than expected for February and March 2011. CONCLUSION The 2010 FIFA World Cup was followed about 9months afterwards by a significant increase in the sex ratio at birth. The main mechanism driving the observed increase in the sex ratio at birth in South Africa is most likely more frequent sexual intercourse at population level during the tournament.
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James WH. Studies of human sex ratios at birth may lead to the understanding of several forms of pathology. Hum Biol 2015; 85:769-88. [PMID: 25078960 DOI: 10.3378/027.085.0513] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2013] [Indexed: 11/05/2022]
Abstract
This article deals with the problem of the causes of the variation of sex ratio (proportion male) at birth. This problem is common to a number of areas in biology and medicine, for example, obstetrics, neurology/psychiatry, parasitology, virology, oncology, and teratology. It is established that there are signifi cantly biased, but unexplained, sex ratios in each of these fields. Yet workers in them (with the possible exception of virology) have regarded the problem as a minor loose end, irrelevant to the field's major problems. However, as far as I know, no one has previously noted that unexplained biased sex ratios occur, and thus pose (perhaps similar) problems, in all these fields. Here it is suggested that similar sorts of solutions apply in each. Further research is proposed for testing each solution. If the argument here is substantially correct across this range of topics, it may lead to an improved understanding not only of sex ratio but also of some of the pathologies in these specialties.
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Affiliation(s)
- William H James
- The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT UK
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Bae J, Kim S, Schisterman EF, Boyd Barr D, Buck Louis GM. Maternal and paternal serum concentrations of perfluoroalkyl and polyfluoroalkyl substances and the secondary sex ratio. CHEMOSPHERE 2015; 133:31-40. [PMID: 25863705 PMCID: PMC7502273 DOI: 10.1016/j.chemosphere.2015.03.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 02/28/2015] [Accepted: 03/08/2015] [Indexed: 05/05/2023]
Abstract
Select persistent environmental chemicals have been associated with a reduction in the secondary sex ratio (SSR), or the ratio of male to female live births. We evaluated preconception maternal, paternal, and couple serum concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in relation to the SSR, given the absence of previous investigation. Two hundred thirty-three couples from Michigan and Texas were enrolled prior to conception and prospectively followed through delivery of a singleton birth, 2005-2009. Maternal and paternal serum concentrations (ng mL(-1)) were measured at baseline for seven PFASs. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for a male birth, after adjusting for potential confounders. When maternal and paternal PFAS concentrations were modeled jointly, five of the seven PFASs, including the two most prominent PFASs, perfluorooctane sulfonic acid and perfluorooctanoic acid, were not significantly associated with the SSR. However, paternal N-methyl-perfluorooctane sulfonamidoacetic acid (MeFOSAA) and perfluorononanoic acid (2nd versus 1st tertile, OR, 0.43, 95% CI, 0.21-0.88) were significantly associated with an excess of female births. Meanwhile, a dose-response relation was observed only for paternal MeFOSAA (2nd versus 1st tertile, OR, 0.53, 95% CI, 0.26-1.10; 3rd versus 1st tertile, OR, 0.34, 95% CI, 0.13-0.89). This study suggests a possible dose-response relation between a less prevalent PFAS and a reversal in the SSR, though the underlying mechanisms remain unknown and the findings await corroboration to eliminate other explanations including chance.
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Affiliation(s)
- Jisuk Bae
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA; Department of Preventive Medicine, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17-gil, Nam-gu, Daegu 705-718, Republic of Korea.
| | - Sungduk Kim
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA
| | - Enrique F Schisterman
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA
| | - Dana Boyd Barr
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322, USA
| | - Germaine M Buck Louis
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322, USA
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Bae J, Kim S, Kannan K, Buck Louis GM. Couples' urinary bisphenol A and phthalate metabolite concentrations and the secondary sex ratio. ENVIRONMENTAL RESEARCH 2015; 137:450-457. [PMID: 25677702 PMCID: PMC4355045 DOI: 10.1016/j.envres.2014.11.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/23/2014] [Accepted: 11/23/2014] [Indexed: 05/30/2023]
Abstract
With limited research focusing on non-persistent chemicals as exogenous factors affecting human sex selection, this study aimed to evaluate the association of urinary bisphenol A (BPA) and phthalate metabolite concentrations with the secondary sex ratio (SSR), defined as the ratio of male to female live births. The current analysis is limited to singleton live births (n=220, 43.9%) from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study, in which couples discontinuing contraception with the intention of becoming pregnant were enrolled and followed while trying for pregnancy and through delivery for those achieving pregnancy. Using modified Poisson regression models accounting for potential confounders, we estimated the relative risks (RRs) of a male birth per standard deviation change in the log-transformed maternal, paternal, and couple urinary BPA and 14 phthalate metabolite concentrations (ng/mL) measured upon enrollment. When maternal and paternal chemical concentrations were modeled jointly, paternal BPA (RR, 0.77; 95% confidence interval [CI], 0.62-0.95) and mono-isobutyl phthalate (RR, 0.82; 95% CI, 0.67-1.00) were significantly associated with a female excess. Contrarily, maternal BPA (RR, 1.16; 95% CI, 1.03-1.31), mono-isobutyl phthalate (RR, 1.28; 95% CI, 1.06-1.54), mono-benzyl phthalate (RR, 1.31; 95% CI, 1.08-1.58), and mono-n-butyl phthalate (RR, 1.24; 95% CI, 1.01-1.51) were significantly associated with a male excess. These findings underscore varying patterns for the SSR in relation to parental exposures. Given the absence of previous investigation, these partner-specific associations of non-persistent chemicals with the SSR need future corroboration.
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Affiliation(s)
- Jisuk Bae
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Boulevard, Rockville, MD 20852, USA; Department of Preventive Medicine, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17-gil Nam-gu, Daegu 705-718, Republic of Korea.
| | - Sungduk Kim
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Boulevard, Rockville, MD 20852, USA.
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA.
| | - Germaine M Buck Louis
- Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 6100 Executive Boulevard, Rockville, MD 20852, USA.
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A further note on the rises in sex ratio at birth during and just after the two World Wars. J Theor Biol 2014; 363:404-11. [DOI: 10.1016/j.jtbi.2014.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 07/30/2014] [Accepted: 08/01/2014] [Indexed: 11/22/2022]
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18
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Catalano R, Yorifuji T, Kawachi I. Natural selection in utero: evidence from the Great East Japan Earthquake. Am J Hum Biol 2013; 25:555-9. [PMID: 23754635 DOI: 10.1002/ajhb.22414] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVES Controversy remains over whether declines in male births reported after population stressors result from either or both reduced conception of males or increased selection in utero against male fetuses. We use monthly birth cohorts to determine if Japanese male births following the Great East Japan Earthquake of 2011 fell below levels expected from female births and from history (i.e., autocorrelation) among cohorts exposed to the Earthquake at or after conception. METHODS We apply interrupted time-series methods to 69 months (i.e., April, 2006 through December, 2011) of birth data from the most and least affected prefectures as well as from the remainder of Japan. We estimate expected male births from female births and from autocorrelation. RESULTS Findings varied by distance from the greatest damage but suggest sensitive periods both early and late in gestation when population stressors may induce selection against males in utero. Support for reduced conception of males appeared only in the prefectures most damaged by the Earthquake. CONCLUSIONS Results align with the claim that natural selection has conserved mechanisms that reduce the odds of a male live birth during stressful times by reducing the conception of males and by increasing the rate of spontaneous abortion among male fetuses.
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Affiliation(s)
- R Catalano
- School of Public Health, University of California, Berkeley, CA 94720, USA.
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19
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Geographic clustering of the secondary sex ratio in Japan: association with demographic attributes. J Biosoc Sci 2013; 45:279-84. [PMID: 23520608 DOI: 10.1017/s0021932012000508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The secondary sex ratio (SSR) has been suggested to decrease with adverse physical and psychological environments. Previous studies have focused on reduced SSR under adverse conditions, such as war, terrorism attack and earthquake, but few studies have investigated fluctuations in SSR in moderately adverse environments. This study analysed municipality-level vital statistics records in Japan collected between 1998 and 2002 to identify high-SSR clusters and low-SSR clusters with spatial-scan statistics. In 999 runs of simulation, high- and low-SSR clusters were detected but fewer than 950 times, indicating that SSR was not geographically clustered in Japan if type I error of 5% was adopted. Explorative analyses comparing demographic attributes between high-SSR clusters and low-SSR clusters that were detected more than 500 times in 999 runs of simulation, showed that rate of spontaneous abortion, rate of artificial abortion and divorce rate were higher in low-SSR clusters, while male life expectancy, female life expectancy and total fertility rate were higher in a high-SSR cluster.
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Abstract
The theory of developmental programming suggests that diseases such as the metabolic syndrome may be ‘programmed’ by exposure to adverse stimuli during early development. The developmental programming literature encompasses the study of a wide range of suboptimal intrauterine environments in a variety of species and correlates these with diverse phenotypic outcomes in the offspring. At a molecular level, a large number of variables have been measured and suggested as the basis of the programmed phenotype. The range of both dependent and independent variables studied often makes the developmental programming literature complex to interpret and the drawing of definitive conclusions difficult. A common, though under-explored, theme of many developmental programming models is a sex difference in offspring outcomes. This holds true across a range of interventions, including dietary, hypoxic, and surgical models. The molecular and phenotypic outcomes of adversein uteroconditions are often more prominent in male than female offspring, although there is little consideration given to the basis for this observation in most studies. We review the evidence that maternal energy investment in male and female conceptuses may not be equal and may be environment dependent. It is suggested that male and female development could be viewed as separate processes from the time of conception, with differences in both timing and outcomes.
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Parental status and gender preferences for children: is differential fertility stopping consistent with the trivers-willard hypothesis? J Biosoc Sci 2012; 45:683-704. [PMID: 22989525 DOI: 10.1017/s0021932012000557] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Based on evolutionary reasoning, Trivers & Willard (1973) predicted status-biased sex composition and parental investment with son-preferencing effects in higher, and daughter-preferencing effects in lower status groups. Previous research shows mixed results. This study uses event-history methods and Swedish register data to study one possible mechanism in isolation: do parents in different status groups vary in their proclivities to continue fertility based on the sex composition of previous offspring? The results show no support for the Trivers-Willard hypothesis on a wide range of different status indicators. Future research on the stated hypothesis should focus on physiological rather than behavioural mechanisms.
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Eisenberg ML, Murthy L, Hwang K, Lamb DJ, Lipshultz LI. Sperm counts and sperm sex ratio in male infertility patients. Asian J Androl 2012; 14:683-6. [PMID: 22842703 DOI: 10.1038/aja.2012.58] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In recent years, investigators have noted a trend toward a declining proportion of male births in many industrialized nations. While men bear the sex-determining chromosome, the role of the female partner as it pertains to fertilization or miscarriage may also alter the gender ratio. We attempted to determine a man's secondary sex ratio (F1 generation) by directly examining the sex chromosomes of his sperm. We examined our male infertility clinic database for all men who had undergone a semen fluorescence in situ hybridization (FISH). Patient demographic and semen parameters were recorded. Chi-squared analysis was used to compare gender ratios (Y chromosomes/total chromosomes). Multivariable logistic regression was used to predict the odds of possessing a Y-bearing sperm after accounting for demographic and semen parameters. A total of 185 men underwent sperm FISH. For the entire cohort, the proportion of Y chromosome-bearing sperm was 51.5%. Men with less than five million motile sperm had a significantly lower proportion of Y chromosome-bearing sperm (50.8%) compared to men with higher sperm counts (51.6%; P=0.02). After multivariable adjustment, a higher sperm concentration, total motile sperm count and semen volume significantly increased the odds of having a Y chromosome-bearing sperm (P<0.01). As a man's sperm production declines, so does the proportion of Y chromosome-bearing sperm. Thus, a man's reproductive potential may predict his ability to sire male offspring.
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Affiliation(s)
- Michael L Eisenberg
- Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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23
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James WH. The relevance of the epidemiology of human sex ratios at birth to some medical problems. Paediatr Perinat Epidemiol 2012; 26:181-9. [PMID: 22471677 DOI: 10.1111/j.1365-3016.2012.01267.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human sex ratio (proportion male at birth) shows considerable variation which is central to reproductive epidemiology. For example, it has reportedly shown significant secular trends and wartime variation, and it has shown replicated variation with parental exposure to several deleterious chemicals. However, scientific progress in identifying the causes of these forms of variation has been very slow and, as described here, this has elicited some scepticism. Benefits may be expected from identifying these causes. Two (non-competing) hypotheses have emerged, the first relating to the hormonal regulation of sex ratio at conception, and the second to the sex-selective effects of stressors during pregnancy. It is shown here that if the first of these hypotheses was substantially correct, it would illuminate a number of scientific and medical problems, for example, the causes of autism and of selected sex-related congenital malformations and obstetric pathologies.
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Affiliation(s)
- William H James
- Department of Genetics, Evolution and Environment, University College London, London, UK.
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Rosenfeld CS. Periconceptional influences on offspring sex ratio and placental responses. Reprod Fertil Dev 2012; 24:45-58. [DOI: 10.1071/rd11906] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Maternal diet and secondary factors can strikingly influence fetal outcomes, including biasing offspring sex ratio and altering the molecular biological responses of the conceptus, namely within the placenta. Alterations in the in utero environment might also lead to profound developmental origin of health and disease (DOHaD) outcomes into adulthood, including increased risk for cardiovascular disease, obesity and cancer, with males in general being at greater risk for these diseases. Female mice maintained on a very high fat (VHF) diet birth more sons than those on a chow-based and low fat (LF), high carbohydrate diet, with the latter group producing more daughters. However, neither the underlying mechanisms that contribute to this shift in offspring sex ratio nor when they occur during pregnancy have been resolved. In this review, we consider the evidence that maternal diet and other factors influence secondary sex ratio in a variety of species, including humans, and discuss when this skewing might occur. Additionally, we examine how fetal sex and maternal diet influences gene expression patterns in the mouse placenta, which serves as the primary nutrient acquisition and communication organ between the mother and her developing pups. These adaptations to diet observed as changes in gene expression are likely to provide insight into how the placenta buffers the fetus proper from environmental shifts in nutrient availability during pregnancy and whether male and female conceptuses respond differently to such challenges.
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Variation of human sex ratios at birth by the sex combinations of the existing sibs, and by reproductive stopping rules: comments on Garenne (2009). J Biosoc Sci 2011; 43:751-60, author reply 761-3. [PMID: 21767426 DOI: 10.1017/s0021932011000319] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Garenne (2009) presented data on the sex ratio of a present birth by the numbers of previous brothers and sisters. In unisexual sibships, the probability of a further girl increases with the number of previous girls; and the probability of a further boy increases with the number of previous boys. Garenne noted that there is an asymmetry in that the effect is stronger with regard to girls than boys. He was uncertain of the cause of this. Here I suggest a potential solution to this problem. Garenne also seems to imply that parental reproductive stopping rules cause heterogeneity of sex ratios. I suggest that they may reveal it - but do not cause it. Moreover, I suggest that the effects of such stopping rules may be counter-intuitive.
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Rocheleau CM, Bertke SJ, Deddens JA, Ruder AM, Lawson CC, Waters MA, Hopf NB, Riggs MA, Whelan EA. Maternal exposure to polychlorinated biphenyls and the secondary sex ratio: an occupational cohort study. Environ Health 2011; 10:20. [PMID: 21418576 PMCID: PMC3070618 DOI: 10.1186/1476-069x-10-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 03/18/2011] [Indexed: 05/29/2023]
Abstract
BACKGROUND Though commercial production of polychlorinated biphenyls was banned in the United States in 1977, exposure continues due to their environmental persistence. Several studies have examined the association between environmental polychlorinated biphenyl exposure and modulations of the secondary sex ratio, with conflicting results. OBJECTIVE Our objective was to evaluate the association between maternal preconceptional occupational polychlorinated biphenyl exposure and the secondary sex ratio. METHODS We examined primipara singleton births of 2595 women, who worked in three capacitor plants at least one year during the period polychlorinated biphenyls were used. Cumulative estimated maternal occupational polychlorinated biphenyl exposure at the time of the infant's conception was calculated from plant-specific job-exposure matrices. A logistic regression analysis was used to evaluate the association between maternal polychlorinated biphenyl exposure and male sex at birth (yes/no). RESULTS Maternal body mass index at age 20, smoking status, and race did not vary between those occupationally exposed and those unexposed before the child's conception. Polychlorinated biphenyl-exposed mothers were, however, more likely to have used oral contraceptives and to have been older at the birth of their first child than non-occupationally exposed women. Among 1506 infants liveborn to polychlorinated biphenyl-exposed primiparous women, 49.8% were male; compared to 49.9% among those not exposed (n = 1089). Multivariate analyses controlling for mother's age and year of birth found no significant association between the odds of a male birth and mother's cumulative estimated polychlorinated biphenyl exposure to time of conception. CONCLUSIONS Based on these data, we find no evidence of altered sex ratio among children born to primiparous polychlorinated biphenyl-exposed female workers.
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Affiliation(s)
- Carissa M Rocheleau
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
| | - Stephen J Bertke
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
- Department of Mathematical Science, University of Cincinnati, Cincinnati, Ohio, USA
| | - James A Deddens
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
- Department of Mathematical Science, University of Cincinnati, Cincinnati, Ohio, USA
| | - Avima M Ruder
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
| | - Christina C Lawson
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
| | - Martha A Waters
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
- Division of Applied Research and Technology; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
| | - Nancy B Hopf
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
- Institut universitaire romand de Santé au Travail/Institute for Work and Health (IST), Lausanne, Switzerland
| | - Margaret A Riggs
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
- Coordinating Office for Terrorism, Preparedness and Emergency Response (Kentucky Department for Public Health); Centers for Disease Control and Prevention; Frankfort, Kentucky, USA
| | - Elizabeth A Whelan
- Division of Surveillance, Hazard Evaluations and Field Studies; Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; Cincinnati, Ohio, USA
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THE CATEGORIES OF EVIDENCE RELATING TO THE HYPOTHESIS THAT MAMMALIAN SEX RATIOS AT BIRTH ARE CAUSALLY RELATED TO THE HORMONE CONCENTRATIONS OF BOTH PARENTS AROUND THE TIME OF CONCEPTION. J Biosoc Sci 2010; 43:167-84. [DOI: 10.1017/s0021932010000660] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryThis note categorizes the evidence for the hypothesis that mammalian offspring sex ratios (proportions male) are causally related to the hormone levels of both parents around the time of conception. Most of the evidence may be acknowledged to be correlational and observational. As such it might be suspected of having been selected; or of having been subject to other forms of bias or confounding; or, at any rate, of being inadequate as a firm basis for causal inference. However, there are other types of evidence that are not vulnerable to these types of criticism. These are from the following sources: (1) previously neglected data from Nazi Germany and Soviet Russia; (2) fulfilled predictions; (3) genetics; and (4) a network of logically (mathematically) related propositions, for some of which there is overwhelming empirical evidence. It is suggested that this variety of evidence confers greater overall credibility on the hypothesis than would be the case if all the evidence were of the same observational/correlational status. This observational/correlational evidence is tabulated to illustrate its consistency.
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Noorlander A, Geraedts J, Melissen J. Female gender pre-selection by maternal diet in combination with timing of sexual intercourse – a prospective study. Reprod Biomed Online 2010; 21:794-802. [DOI: 10.1016/j.rbmo.2010.08.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 07/29/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
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Villamor E, Dekker L, Svensson T, Cnattingius S. Accuracy of the Chinese lunar calendar method to predict a baby's sex: a population-based study. Paediatr Perinat Epidemiol 2010; 24:398-400. [PMID: 20618730 DOI: 10.1111/j.1365-3016.2010.01129.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We estimated the accuracy of a non-invasive, inexpensive method (the Chinese lunar calendar, CLC) to predict the sex of a baby from around the time of conception, using 2,840,755 singleton births occurring in Sweden between 1973 and 2006. Maternal lunar age and month of conception were estimated, and used to predict each baby's sex, according to a published algorithm. Kappa statistics were estimated for the actual vs. the CLC-predicted sex of the baby. Overall kappa was 0.0002 [95% CI -0.0009, 0.0014]. Accuracy was not modified by year of conception, maternal age, level of education, body mass index or parity. In a validation subset of 1000 births in which we used a website-customised algorithm to estimate lunar dates, kappa was -0.02 [95% CI -0.08, 0.04]. Simulating the misuse of the method by failing to convert Gregorian dates into lunar did not change the results. We conclude that the CLC method is no better at predicting the sex of a baby than tossing a coin and advise against painting the nursery based on this method's result.
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Affiliation(s)
- Eduardo Villamor
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI 48109, USA.
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Zilko CEM. Economic contraction and birth outcomes: an integrative review. Hum Reprod Update 2010; 16:445-58. [PMID: 20085917 DOI: 10.1093/humupd/dmp059] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Previous research has demonstrated an association between economic contraction at both the individual and aggregate level, and adverse health outcomes. Proposed mechanisms include increased psychosocial stress and loss of resources. The aim of this review is to assess the quantity, validity and consistency of empirical evidence examining economic contraction and birth outcomes. METHODS Empirical, English-language articles examining the effects of economic change at either the aggregate or individual level on birthweight, length of gestation, neonatal mortality and the secondary sex ratio were identified using PubMed and ISI Web of Knowledge. Studies were organized by level of analysis and birth outcome and evaluated for internal and external validity. RESULTS One individual-level study reported a strong association between individual shift to inadequate employment and decreased birthweight. Of seven aggregate-level studies on birthweight, five exhibited moderate to strong validity but reported inconsistent findings. Similarly, findings from five studies (four with moderate to strong validity) examining rates of neonatal mortality reported inconsistent findings. Three of four moderate to strong studies reported a reduced secondary sex ratio following economic contraction. CONCLUSIONS Associations between economic contraction and birthweight, neonatal mortality and the secondary sex ratio remain speculative. Consensus on methodology is needed to compare findings across studies. Further research on economic contraction and the secondary sex ratio, as well as individual-level birthweight and length of gestation, is warranted.
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Affiliation(s)
- C E Margerison Zilko
- Division of Epidemiology, School of Public Health, University of California, Berkeley, CA 94720, USA.
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James WH. A plea for data on the sexes of human offspring and the time of formation of the zygotes within the fruitful cycle. Hum Reprod 2009; 25:805. [PMID: 20007615 DOI: 10.1093/humrep/dep365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Grant VJ. Wartime sex ratios: Stress, male vulnerability and the interpretation of atypical sex ratio data. ACTA ACUST UNITED AC 2009. [DOI: 10.1556/jep.7.2009.4.5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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When does the sex ratio of offspring of the paternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure decrease: in the spermatozoa stage or at fertilization? Reprod Toxicol 2009; 29:68-73. [PMID: 19808090 DOI: 10.1016/j.reprotox.2009.09.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Accepted: 09/26/2009] [Indexed: 11/21/2022]
Abstract
Recent animal experiments confirmed that paternal 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure decreases the sex ratio of offspring at birth without altering litter size. However, the timing of this decrease remained unclear. Male mice were administered TCDD at 7-12 weeks of age and mated with non-treated females. The Y-bearing/X-bearing sperm ratio was examined by real-time PCR and FISH methods, and the sex ratio of the 2-cell embryos collected from non-treated females that had been mated with TCDD-exposed males were investigated by nested PCR. The Y-bearing/X-bearing sperm ratio was not significantly decreased in the TCDD group. However, the sex ratio of the 2-cell embryos of the TCDD group was significantly lower than that of the control group. These results may have resulted from a decrease in fertility of Y-bearing sperm. Thus, the results of this study suggested that the sex ratio of the offspring was decreased at fertilization and not during the spermatozoa stage.
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Menstrual Cycle Characteristics and Offspring Sex Ratio. Epidemiology 2009; 20:782. [DOI: 10.1097/ede.0b013e3181afef60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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SEXUAL ACTIVITY AND PROSTATE CANCER RISK IN MEN DIAGNOSED AT A YOUNGER AGE. BJU Int 2009; 103:1142-3. [DOI: 10.1111/j.1464-410x.2009.08553_2.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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James WH. The variances of the distributions of the combinations of the sexes within mammalian litters: notes to mark the centenary of the problem. J Theor Biol 2009; 259:264-8. [PMID: 19336236 DOI: 10.1016/j.jtbi.2009.03.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 02/19/2009] [Accepted: 03/13/2009] [Indexed: 11/16/2022]
Abstract
It is 100 years since Gini noted that in some samples of litters of mice and rabbits, the variances of the distributions of the combinations of the sexes are sub-binomial. In other words, in contrast with binomial expectation, there are too many litters in which the sexes are equally balanced, and there are too few unisexual litters. In the intervening years, this finding has been replicated in a number of further species, but no explanation has become established. Potential explanations are reviewed here, and it is suggested that the most likely cause is that, at the time of formation of the zygotes, p, the probability that a zygote will be male, varies from one zygote to another within litters, thus constituting an example of Poisson variation. And it is a standard result in probability theory that such variation causes sub-binomial variance.
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Affiliation(s)
- William H James
- The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW 1 2 HE, UK.
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The variations of human sex ratio at birth during and after wars, and their potential explanations. J Theor Biol 2009; 257:116-23. [DOI: 10.1016/j.jtbi.2008.09.028] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/14/2008] [Accepted: 09/23/2008] [Indexed: 11/19/2022]
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