Association between Bone Lead Concentration and Aggression in Youth from a Sub-Cohort of the Birth to Twenty Cohort.

BACKGROUND: An association between blood-lead levels and aggression has been demonstrated in children and adolescent youth in South Africa. However, there are limited studies that have assessed aggression as an outcome for cumulative lead exposure using bone lead concentration. This study aims to assess the association between bone lead concentration and aggressive behaviour among a sample of youth in South Africa. METHODS: Bone lead in 100 participants (53 males and 47 females) recruited and followed in the Birth to Twenty (BT20) Cohort were measured using 109 Cd-based, K-shell X-ray fluorescence (KXRF). The Buss-Perry Aggression questionnaire was used to measure aggressive behaviour. Linear regression models were fitted to determine the association between aggression score for physical, verbal, anger and hostility and bone lead, adjusting for known confounders. RESULTS: A one-microgram-per-gram increase in bone lead was found to increase the score for all four scales of aggression, but significantly only for anger (ß = 0.2 [95% CI 0.04-0.370]). Psychosocial factors such as a history of family violence and exposure to neighbourhood crime were significant predictors for aggression. CONCLUSIONS: The study provides a preliminary overview of the relationship between cumulative lead exposure and behavioural problems such as aggression. A larger sample, across exposed communities, may prove more definitive in further investigating the association between these two important public health factors and to maximize generalizability.

Environmental lead exposure and pubertal trajectory classes in South African adolescent males and females.

The effects of environmental lead exposure in the neuro-endocrine system have been shown to impact the maturation and tempo of puberty development in adolescents. In low and middle income countries very little is known regarding the detrimental health effects of childhood lead exposure with regard to the tempo of puberty development. To help address this gap in data, we examined the association between lead exposure and puberty progression in males and females. Study participants from the urban Birth to Twenty Plus (BT20+) birth cohort in Soweto-Johannesburg, South Africa with data for blood lead levels at age 13years, cord blood lead levels, pubic hair development and breast development in females, and pubic hair development and genital development in males, were included in this study. The sample comprised 1416 study participants (n=684 females). Pubertal development trajectory classes were defined using Latent Class Growth Analysis. Data were examined for (i) an association between cord blood lead levels and pubertal trajectory classes; and (ii) an association between blood lead levels at age 13years and pubertal trajectory classes. In females, there was an association between adolescent elevated blood lead levels (≥5µg/dL) and lower level of maturation at age 9years and slower progression of pubic hair and breast development (relative risk ratio (RRR)=0.45, p<0.0001; 95% CI (0.29-0.68)) and (RRR=0.46, p<0.01; 95% CI (0.27-0.77)), respectively. In males, elevated blood lead levels at birth were associated with slower tempo of pubic hair development (RRR=0.20, p<0.05). Findings from this study suggest a possible role for environmental lead in altering pubertal development in South African adolescents as shown by slower tempo of progression through the Tanner stages pubertal development in females and males. There were also gender-differences between the effects of prenatal and postnatal lead exposure during pubertal development.

The association between environmental lead exposure with aggressive behavior, and dimensionality of direct and indirect aggression during mid-adolescence: Birth to Twenty Plus cohort.

Chronic lead exposure is associated with neurological ill-health including anti-social behavior such as aggressive behavior. The main aim of this study was to examine the association between lead exposure at 13years old and dimensions of aggressive behavior during mid-adolescence. The study sample included 508 males and 578 females in mid-adolescence (age 14 to 15years) from the Birth to Twenty Plus cohort in Johannesburg, South Africa. Blood samples collected at age 13years were used to measure blood lead levels. Seventeen items characterizing aggression from the Youth Self Report questionnaire were used to examine aggressive behavior. Principal Component Analysis was used to derive composite variables from the original data for aggressive behavior; and data were examined for an association between blood lead levels and dimensionality of direct and indirect aggression and disobedience during mid-adolescence. We also examined the dimensions of aggression during mid-adolescence in relation to gender and socio-demographic factors. Blood lead levels ranged from 1 to 28.1µg/dL. Seventy two percent of males and 47.7% of females in the study had blood lead levels ≥5µg/dL. There was a positive association between elevated blood lead levels and direct aggression (p<0.05). Being male was positively associated with direct aggression (p<0.001) but, negatively associated with indirect aggression (p<0.001). Maternal education and age at birth were negatively associated with direct aggression during mid-adolescence. The significant association between elevated blood lead levels and direct aggressive behavior observed in this study may shed light on a possible environmental toxicological contribution to aggressive behavior in South African youth; and most importantly the type of aggressive behavior associated to lead exposure.

The association between elevated blood lead levels and violent behavior during late adolescence: The South African Birth to Twenty Plus cohort.

Epidemiological studies have shown the adverse neuro-behavioral health effects of lead exposure among children, in particular. However, there is lack evidence in this regard from developing countries. The main aim of this study was to assess the association between blood lead levels (BLLs) during early adolescence and violent behavior in late adolescence. Our study sample from the Birth to Twenty Plus cohort in Soweto-Johannesburg, South Africa included 1332 study participants (684 females). BLLs were measured using blood samples collected at age 13years. Violent behavior was evaluated using data collected at ages 15 to 16years using the Youth Self Report questionnaire. First, bivariate analysis was used to examine data for an association between lead exposure in early adolescence and violent behavior items during late adolescence. Principal Component Analysis (PCA) was used for dimensionality reduction and six violent behavior components were derived. Data were further analyzed for an association between BLLs at age 13years and violent behavior using PCA derived components; to determine the specific type(s) of violent behavior associated with lead exposure. Median whole BLLs were 5.6µg/dL (p<0.001). Seventy five percent of males and 50% of females had BLLs≥5µg/dL. BLLs ranging from 5 to 9.99µg/dL were associated with physical violence (p=0.03) and BLLs≥10µg/dL were associated physical violence and fighting (p=0.02 and p=0.01, respectively). When data were analyzed using continuous BLLs physical violence was associated with lead exposure (p<0.0001). Furthermore, males were more likely to be involved in violence using a weapon (p=0.01), physical violence (p<0.0001), and robbing others (p<0.05) compared to females. The results from this study show the severe nature of violent behavior in late adolescence associated with childhood lead exposure. They highlight the urgent need for preventive measures against lead exposure among children in low or middle income countries such as South Africa.

How ready are our health systems to implement prevention of mother to child transmission Option B+?

In January 2015, the South African National Department of Health released new consolidated guidelines for the prevention of mother to child transmission (PMTCT) of HIV, in line with the World Health Organization's (WHO) PMTCT Option B+. Implementing these guidelines should make it possible to eliminate mother to child transmission (MTCT) of HIV and improve long-term maternal and infant outcomes. The present article summarises the key recommendations of the 2015 guidelines and highlights current gaps that hinder optimal implementation; these include late antenatal booking (as a result of poor staff attitudes towards 'early bookers' and foreigners, unsuitable clinic hours, lack of transport to facilities, quota systems being applied to antenatal clients and clinic staff shortages); poor compliance with rapid HIV testing protocols; weak referral systems with inadequate follow-up; inadequate numbers of laboratory staff to handle HIV-related monitoring procedures and return of results to the correct facility; and inadequate supply chain management, leading to interrupted supplies of antiretroviral drugs. Additionally, recommendations are proposed on how to address these gaps. There is a need to evaluate the implementation of the 2015 guidelines and proactively communicate with ground-level implementers to identify operational bottlenecks, test solutions to these bottlenecks, and develop realistic implementation plans.

A cross-sectional analytical study of geophagia practices and blood metal concentrations in pregnant women in Johannesburg, South Africa.

BACKGROUND: Geophagia, a form of pica, has been shown to be widely practised in sub-Saharan Africa, especially among pregnant women. OBJECTIVE: To assess the prevalence of geophagia and examine exposure to selected metals and associated risk factors in women attending an antenatal clinic at Rahima Moosa Mother and Child Hospital, Johannesburg, South Africa, during June and July 2010. METHODS: We conducted a cross-sectional study on a convenience sample of 307 pregnant women, ranging in age from 18 to 46 years. Structured interviews were conducted to understand geophagia practices. Blood samples were collected to determine haemoglobin values and concentrations of arsenic, cadmium, mercury and lead. Statistical analyses using the χ2 test, Wilcoxon's rank-sum test and logistic regression analyses were performed as appropriate. RESULTS: Mean parity was 1.4 and the mean (standard deviation) gestational age 30.3 (6.0) weeks. Geophagia was reported by 60 women (19.5%), and the majority purchased soil from street vendors (83.3%). The prevalence of anaemia in the study sample was 16.9% (95% confidence interval 13.1 - 21.6%). Geophagic women had significantly higher blood lead levels than non-geophagic women (2.1 v. 1.4 µg/dl; p<0.001). Anaemia, the use of African traditional medicines and craving of non-nutritive substances in a previous pregnancy were associated with geophagia. CONCLUSIONS: Geophagia is practised by a considerable proportion of pregnant women in Johannesburg, especially migrant women. Greater vigilance in respect of pica, especially geophagia, may be needed as part of antenatal care programmes to avoid potentially detrimental health effects of the practice.