Exploratory Spatial Data Analysis of Congenital Malformations (CM) in Israel, 2000–2006

"Residential greenness, gestational diabetes mellitus (GDM) and microbiome diversity during pregnancy"

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with reduced gut microbiota richness that was also reported to differ significantly between those living in rural compared to urban environments. Therefore, our aim was to examine the associations between greenness and maternal blood glucose levels and GDM, with microbiome diversity as a possible mediator in these associations.

METHODS

Pregnant women were recruited between January 2016 and October 2017. Residential greenness was evaluated as mean Normalized Difference Vegetation Index (NDVI) within 100, 300 and 500 m buffers surrounding each maternal residential address. Maternal glucose levels were measured at 24-28 weeks of gestation and GDM was diagnosed. We estimated the associations between greenness and glucose levels and GDM using generalized linear models, adjusting for socioeconomic status and season at last menstrual period. Using causal mediation analysis, the mediation effects of four different indices of microbiome alpha diversity in first trimester stool and saliva samples were assessed.

RESULTS

Of 269 pregnant women, 27 participants (10.04%) were diagnosed with GDM. Although not statistically significant, adjusted exposure to medium tertile levels of mean NDVI at 300 m buffer had lower odds of GDM (OR = 0.45, 95% CI: 0.16, 1.26, p = 0.13) and decreased change in mean glucose levels (β = -6.28, 95% CI: 14.91, 2.24, p = 0.15) compared to the lowest tertile levels of mean NDVI. Mixed results were observed at 100 and 500 m buffers, and when comparing highest tertile levels to lowest. No mediation effect of first trimester microbiome on the association between residential greenness and GDM was observed, and a small, possibly incidental, mediation effect on glucose levels was observed.

CONCLUSION

Our study suggests possible associations between residential greenness and glucose intolerance and risk of GDM, though without sufficient evidence. Microbiome in the first trimester, while involved in GDM etiology, is not a mediator in these associations. Future studies in larger populations should further examine these associations.

Spatial Clusters of Children with Cleft Lip and Palate and Their Association with Polluted Zones in the Monterrey Metropolitan Area

This study examines the spatial structure of children with cleft lip and palate (CLP) and its association with polluted areas in the Monterrey Metropolitan Area (MMA). The Nearest Neighbor Index (NNI) and the Spatial Statistical Scan (SaTScan) determined that the CLP cases are agglomerated in spatial clusters distributed in different areas of the city, some of them grouping up to 12 cases of CLP in a radius of 1.2 km. The application of the interpolation by empirical Bayesian kriging (EBK) and the inverse distance weighted (IDW) method showed that 95% of the cases have a spatial interaction with values of particulate matter (PM₁₀) of more than 50 points. The study also shows that 83% of the cases interacted with around 2000 annual tons of greenhouse gases. This study may contribute to other investigations applying techniques for the identification of environmental and genetic factors possibly associated with congenital malformations and for determining the influence of contaminating substances in the incidence of these diseases, particularly CLP.

Spatial pattern and variations in the prevalence of congenital heart disease in children aged 4-18 years in the Qinghai-Tibetan Plateau

PURPOSE

This study aimed to investigate the spatial distribution pattern of the prevalence of congenital heart disease (CHD) in children in Qinghai-Tibetan Plateau (QTP), a high-altitude region in China.

METHODS

Epidemiological data from a survey on the prevalence of CHD in Qinghai Province including 288,066 children (4-18 years) were used in this study. The prevalence and distribution pattern of CHD was determined by sex, CHD subtype, and nationality and altitude. Spatial pattern analysis using Getis-Ord Gi^⁎ was used to identify the spatial distribution of CHD. Bayesian spatial binomial regression was performed to examine the relationship between the prevalence of CHD and environmental risk factors in the QTP.

RESULTS

The prevalence of CHD showed a significant spatial clustering pattern. The Tibetan autonomous prefecture of Yushu (average altitude > 4000 m) and the Mongolian autonomous county of Henan (average altitude > 3600 m) in Huangnan had the highest prevalence of CHD. Univariate analysis showed that with ascending altitude, the total prevalence of CHD, that in girls and boys with CHD, and that of the subtypes PDA and ASD increasing accordingly. Thus, environmental factors greatly contributed to the prevalence of CHD.

CONCLUSIONS

The prevalence of CHD shows significant spatial clustering pattern in the QTP. The CHD subtype prevalence clustering pattern has statistical regularity which would provide convenient clues of environmental risk factors. Our results may provide support to make strategies of CHD prevention, to reduce the incidence of CHD in high altitude regions of China.

A population-based study of prevalence trends and geospatial analysis of hypospadias and cryptorchidism compared with non-endocrine mediated congenital anomalies

INTRODUCTION

Several reports have suggested an increase in the prevalence of hypospadias and cryptorchidism over the last few decades. Endocrine disruption caused by exposure to environmental chemicals has been postulated as a possible cause.

OBJECTIVES

The objectives of our study were: 1) to determine whether the prevalence of hypospadias and cryptorchidism is increasing compared with other congenital anomalies not known to be mediated by endocrine factors; and 2) to perform a geospatial analysis of these congenital malformations looking for clustering that could offer insight into environmental risk factors.

MATERIAL AND METHODS

Data were obtained from the Nova Scotia ATLEE Perinatal Database containing the perinatal records of all live births in Nova Scotia, Canada since 1988. Records from 1988 to 2013 defined the study cohort. Overall prevalence rates and prevalence trends by year were calculated for hypospadias, cryptorchidism, gastroschisis, and clubfoot. County of residence was collected and spatial autocorrelation testing for clustering was performed for each of the congenital anomalies.

RESULTS

There were 258,147 live births during the study period. Overall prevalence rates for the four malformations over the study period were: hypospadias 78 per 10,000 male births, cryptorchidism 75 per 10,000 male births, clubfoot 24 per 10,000 total births, and gastroschisis 4 per 10,000 total births. Incidence rate ratios per year for hypospadias, cryptorchidism, clubfoot, and gastroschisis were 1.00 (0.99-1.01), 0.99 (0.98-1.00), 0.98 (0.97-0.99), and 1.04 (1.04-1.07), respectively. During the study period, the prevalence rates in the region were unchanged for hypospadias, slightly reduced for cryptorchidism and clubfoot, and rising for gastroschisis (Figure). Spatial autocorrelation testing revealed statistically significant clustering for hypospadias (p = 0.03) and cryptorchidism (p = 0.03), while no spatial autocorrelation was observed for the other malformations.

DISCUSSION

Contrary to previous studies we show that hypospadias and cryptorchidism prevalence rates are not increasing over time in our region. Nonetheless, rates for these conditions in our area are high compared with other regions of the world. Local clustering of these congenital anomalies without clustering of the control, non-endocrine mediated congenital malformations supports a possible unique spatial distribution associated with environmental exposure. The hotspots identified for hypospadias and cryptorchidism are associated with intense agricultural activity.

CONCLUSIONS

Our study found no increase in hypospadias and cryptorchidism prevalence over a 26-year period compared with other congenital anomalies not known to be associated with endocrine factors. Geospatial analysis supports high clustering for hypospadias and cryptorchidism in areas of intense agricultural activity.

Spatial Pattern Detection of Tuberculosis: A Case Study of Si Sa Ket Province, Thailand

This retrospective population-based study was conducted to analyze spatial patterns of tuberculosis (TB) incidence in Si Sa Ket province, Thailand. TB notification data from 2004 to 2008 collected from TB clinics throughout the province was used along with population data to reveal a descriptive epidemiology of TB incidences. Global clustering patterns of the occurrence were assessed by using global spatial autocorrelation techniques. Additionally, local spatial pattern detection was performed by using local spatial autocorrelation and spatial scan statistic methods. The findings indicated clusters of the disease occurred in the study area. More specifically, significantly high-rate clusters were mostly detected in Mueang Si Sa Ket and Khukhan districts, which are located in the northwestern part of the province, while significantly low-rate clusters were persistent in Kantharalak and Benchalak districts, which are located at the southeastern area.

Spatial patterns of the congenital heart disease prevalence among 0- to 14-year-old children in Sichuan Basin, P. R China, from 2004 to 2009

Background

Congenital heart disease (CHD) is the most common type of major birth defects in Sichuan, the most populous province in China. The detailed etiology of CHD is unknown but some environmental factors are suspected as the cause of this disease. However, the geographical variations in CHD prevalence would be highly valuable in providing a clue on the role of the environment in CHD etiology. Here, we investigate the spatial patterns and geographic differences in CHD prevalence among 0- to 14-year-old children, discuss the possible environmental risk factors that might be associated with CHD prevalence in Sichuan Basin from 2004 to 2009.

Methods

The hierarchical Bayesian model was used to estimate CHD prevalence at the township level. Spatial autocorrelation statistics were performed, and a hot-spot analysis with different distance thresholds was used to identify the spatial pattern of CHD prevalence. Distribution and clustering maps were drawn using geographic information system tools.

Results

CHD prevalence was significantly clustered in Sichuan Basin in different spatial scale. Typical hot/cold clusters were identified, and possible CHD causes were discussed. The association between selected hypothetical environmental factors of maternal exposure and CHD prevalence was evaluated.

Conclusions

The largest hot-spot clustering phenomena and the CHD prevalence clustering trend among 0- to 14-year-old children in the study area showed a plausibly close similarity with those observed in the Tuojiang River Basin. The high ecological risk of heavy metal(Cd, As, and Pb)sediments in the middle and lower streams of the Tuojiang River watershed and ammonia–nitrogen pollution may have contribution to the high prevalence of CHD in this area.

Green spaces and adverse pregnancy outcomes

OBJECTIVE

The objective of this study was to evaluate the associations between proximity to green spaces and surrounding greenness and pregnancy outcomes, such as birth weight, low birth weight (LBW), very LBW (VLBW), gestational age, preterm deliveries (PTD) and very PTD (VPTD).

METHODS

This study was based on 39,132 singleton live births from a registry birth cohort in Tel Aviv, Israel, during 2000-2006. Surrounding greenness was defined as the average of satellite-based Normalised Difference Vegetation Index (NDVI) in 250 m buffers and proximity to major green spaces was defined as residence within a buffer of 300 m from boundaries of a major green space (5000 m(2)), based on data constructed from OpenStreetMap. Linear regression (for birth weight and gestational age) and logistic regressions models (for LBW, VLBW, PTD and VPTD) were used with adjustment for relevant covariates.

RESULTS

An increase in 1 interquartile range greenness was associated with a statistically significant increase in birth weight (19.2 g 95% CI 13.3 to 25.1) and decreased risk of LBW (OR 0.84, 95% CI 0.78 to 0.90). Results for VLBW were in the same direction but were not statistically significant. In general, no associations were found for gestational age, PTD and VPTD. The findings were consistent with different buffer and green space sizes and stronger associations were observed among those of lower socioeconomic status.

CONCLUSIONS

This study confirms the results of a few previous studies demonstrating an association between maternal proximity to green spaces and birth weight. Further investigation is needed into the associations with VLBW and VPTD, which has never been studied before.

Ambient temperature and congenital heart defects

STUDY QUESTION

Does maternal exposure during pregnancy to higher ambient temperature increase the risk of congenital heart defects (CHDs)?

SUMMARY ANSWER

Significant associations were found between maternal exposure during pregnancy to higher ambient temperature and CHDs risk especially during the cold season.

WHAT IS KNOWN ALREADY

From rodents to non-human primates, a teratogenic effect of hyperthermic insult has been demonstrated. There are fewer data regarding the effect on the human fetus and specifically the association between maternal exposures during pregnancy to higher ambient temperature and CHDs.

STUDY DESIGN, SIZE, DURATION

This population registry-based cohort study included 135 527 live and stillbirths in the Tel-Aviv region of Israel in 2000-2006.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Two clinical diagnostic groups of isolated cardiac defects (atrial septal defects and ventricular septal defects: n = 542 and 481, respectively) and one group of multiple cardiac defects (defined by the presence of two or more cardiac malformations, n = 607) were studied. Temperature measurements were constructed from ambient stations and used to assess the impact of maternal exposure to average ambient temperature and extreme heat events (daily average temperature above the 90th percentile) during Weeks 3-8 of pregnancy on risk of CHDs. Logistic models, adjusted for sociodemographic covariates, were used to evaluate the associations between temperature and CHDs.

MAIN RESULTS AND THE ROLE OF CHANCE

Overall, we found no significant associations between ambient temperature and CHDs throughout the year, with one exception for multiple CHDs. After stratifying by season of conception, continuous exposure to average ambient temperature and maximum peak temperature (1°C increase) during the cold season increased the risk for multiple CHDs [odds ratio (OR) 1.05, 95% confidence interval (CI): 1.00, 1.10 and OR 1.03, 95% CI: 1.01, 1.05, respectively]. A 1-day increase in extreme heat events increased the risk for multiple CHDs (OR 1.13, 95% CI: 1.06, 1.21) and also for isolated atrial septal defects (OR 1.10, 95% CI: 1.02, 1.19).

LIMITATIONS, REASONS FOR CAUTION

Information both on CHD cases and on ambient temperature was based on registries and it is possible that this may cause some misclassification. In urban areas, pregnant women may be exposed to higher temperatures than recorded by ambient monitors because of the 'heat island effect'. Furthermore, data for the amount of time spent indoors were unavailable and this could have resulted in exposure misclassification.

WIDER IMPLICATIONS OF THE FINDINGS

The findings are important within the context of global climate change, which may have implications for public health in countries with mild winters and hot summers.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Israeli Ministry of Environmental Protection (research grant-7-2-7) and by the Environment and Health Fund (PhD Fellowship Program). There are no competing interests.