Follow-up of the air pollution and the human male-to-female ratio analysis in São Paulo, Brazil: a times series study

Abstract

ObjectivesIn order to assess if ambient air pollution in urban areas could be related to alterations in male/female ratio this study objectives to evaluate changes in ambient particulate matter (PM10) concentrations after implementation of pollution control programmes in São Paulo city and the secondary sex ratio (SRR).Design and methodsA time series study was conducted. São Paulo’s districts were stratified according to the PM10 concentrations levels and were used as a marker of overall air pollution. The male ratio was chosen to represent the secondary sex ratio (SSR=total male birth/total births). The SSR data from each area was analysed according to the time variation and PM10 concentration areas using descriptive statistics. The strength association between annual average of PM10 concentration and SSR was performed through exponential regression, and it was adopted as a statistical significance level of p<0.05.ResultsThe exponential regression showed a negative and significant association between PM10 and SSR. SSR varied from 51.4% to 50.7% in São Paulo in the analysed period (2000–2007). Considering the PM10 average concentration in São Paulo city of 44.72 μg/m3 in the study period, the SSR decline reached almost 4.37%, equivalent to 30 934 less male births.ConclusionsAmbient levels of PM10 are negatively associated with changes in the SSR. Therefore, we can speculate that higher levels of particulate pollution could be related to increased rates of female births.

Inhalation of fine particulate matter during pregnancy increased IL-4 cytokine levels in the fetal portion of the placenta

“…e l s e v i e r . c o m / l o c a t e / t o x l e t and prematurity in humans (Bobak, 2000;Leem et al, 2006;Liu et al, 2003;Pereira et al, 2014;Ritz et al, 2007;Sagiv et al, 2005;Suh et al, 2009) and human and mice litters with a high proportion of females (Lichtenfels et al, 2007;Miraglia et al, 2013). A decrease in the number of viable fetuses and an increase in implantation failure were observed in female mice exposed to air pollution from the 10th day of life (Mohallem et al, 2005).…”

Effects of Fetal Exposure to Asian Sand Dust on Development and Reproduction in Male Offspring

“…Another report indicates that approximately 51% of all human offspring had previously been males, but that a decline in the sex ratio at birth (or secondary sex ratio, SSR) has occurred since the middle of the 20th century [20]. Exponential regression analysis has shown a negative and significant association between particulate matter and SSR in Brazil [21]. However, the effects of fetal ASD exposure on SSR and male reproductive function have not yet been fully elucidated.…”

Effects of Fetal Exposure to Asian Sand Dust on Fetal Development and Reproductive Function in Male Offspring

“…Another report indicates that approximately 51% of all human offspring had previously been males but that a decline in the sex ratio at birth or secondary sex ratio (SSR) has occurred since the middle of the 20th century [20]. Exponential regression analysis has shown a negative and significant association between particulate matter and SSR in Brazil [21]. However, the effects of fetal ASD exposure on SSR and the male reproductive function have not yet been fully elucidated.…”