Penka D. Gatseva

High-nitrate levels in drinking water may be a risk factor for thyroid dysfunction in children and pregnant women living in rural Bulgarian areas.

Nitrate inhibits the accumulation of iodide in thyroid gland. The aim of present study was to evaluate the influence of this ion on the iodine status of two risk population groups. Subjects of study were pregnant women and children aged between 3 and 6 years from two villages in Bulgaria with high- and low-nitrate levels in drinking water. The relative risk of thyroid disorders for the pregnant women living in the village with high-nitrate levels in drinking water expressed as an odds ratio was 5.294 (95% confidence intervals 1.003-27.939; P=0.0454) and was considered as significant. Statistically significant differences were found between the goiter rate in exposed and non-exposed pregnant women. The relative risk of thyroid dysfunction for the children exposed to a high-nitrate level, expressed as an odds ratio was 2.333 (95% confidence intervals 0.8491-6.412; P=0.1396) and was considered as not significant; the goiter prevalence in the exposed children was also not statistically different. The results of the study confirmed the role of high-nitrate level in drinking water as a risk factor for thyroid dysfunction in vulnerable population groups.

Iodine status and goitre prevalence in nitrate-exposed schoolchildren living in rural Bulgaria

Nitrate and perchlorate are well-known water pollutants that are harmful to human health. They may inhibit the accumulation of iodide in the thyroid gland. The present study investigated iodine status and goitre prevalence in schoolchildren aged 7-14 years from two villages in Bulgaria with high and low levels of nitrate, and negligible levels of perchlorate in drinking water. Comparison between the mean and median urinary iodine concentrations of the exposed and non-exposed children showed a statistically significant difference for the boys. A statistically significant difference was also found for goitre prevalence between the exposed and non-exposed children. The relative risk for schoolchildren exposed to a high level of nitrate in drinking water, expressed as an odds ratio, was 3.014 (95% confidence intervals 1.293-7.027; P=0.0105) and this was considered to be significant. This study confirmed that a high level of nitrate in drinking water is a risk factor for thyroid dysfunction in this population.

Iodine Status of Children Living in Areas With High Nitrate Levels in Water

Several researchers have suggested a possible relationship between nitrate intake and the development of goiter in children. The present cross-sectional study included schoolchildren between the ages of 11 and 14 years from 2 villages in Bulgaria with high and low nitrate levels in drinking water. The comparison between the median urinary iodine levels of the total number of exposed (179.0 μg/l) and nonexposed (202.50 μ/l) children showed statistically significant differences. The relative risk for the children exposed to high nitrate levels in drinking water, expressed as the odds ratio, was 8.145 (95% confidence interval = 1.67-39.67). The authors considered this to be very significant. They found a statistically significant difference for the prevalence of goiter among the exposed and nonexposed children. The results of the study confirmed the role of high nitrate levels in drinking water as a health risk factor for thyroid dysfunction.

Evaluation of endemic goiter prevalence in Bulgarian schoolchildren: results from national strategies for prevention and control of iodine-deficiency disorders.

Iodine deficiency is a major health problem worldwide. The environment of the Balkan countries, including Bulgaria, is distinguished for its low iodine content. In 1994, the strategies for the prevention and control of iodine-deficiency disorders were actualized in Bulgaria and universal salt iodization and supplementation for the risk population groups (schoolchildren, pregnant women) were introduced. The aim of this study was to assess the effectiveness of the iodine prophylaxis in schoolchildren, living in an endemic for goiter area after the introduction of salt iodization in Bulgaria. For this purpose, the goiter prevalence and iodine status in 483 schoolchildren (274 boys and 209 girls) aged between 8 and 15 yr, living in an endemic for goiter area in Bulgaria were evaluated. Despite the normalization of iodine supply, mild iodine deficiency on the basis of goiter prevalence (16.15%) and urinary iodine excretion was found. These data indicate the need for reevaluation of the national strategy for prevention of iodine deficiency.

Multiple pathways link urban green- and bluespace to mental health in young adults

Background: A growing body of scientific literature indicates that urban green‐ and bluespace support mental health; however, little research has attempted to address the complexities in likely interrelations among the pathways through which benefits plausibly are realized. Objectives: The present study examines how different plausible pathways between green/bluespace and mental health can work together. Both objective and perceived measures of green‐ and bluespace are used in these models. Methods: We sampled 720 students from the city of Plovdiv, Bulgaria. Residential greenspace was measured in terms of the Normalized Difference Vegetation Index (NDVI), tree cover density, percentage of green areas, and Euclidean distance to the nearest green space. Bluespace was measured in terms of its presence in the neighborhood and the Euclidean distance to the nearest bluespace. Mental health was measured with the 12‐item form of the General Health Questionnaire (GHQ‐12). The following mediators were considered: perceived neighborhood green/bluespace, restorative quality of the neighborhood, social cohesion, physical activity, noise and air pollution, and environmental annoyance. Structural equation modelling techniques were used to analyze the data. Results: Higher NDVI within a 300 m buffer around the residence was associated with better mental health through higher perceived greenspace; through higher perceived greenspace, leading to increased restorative quality, and subsequently to increased physical activity (i.e., serial mediation); through lower noise exposure, which in turn was associated with lower annoyance; and through higher perceived greenspace, which was associated with lower annoyance. Presence of bluespace within a 300 m buffer did not have a straightforward association with mental health owing to competitive indirect paths: one supporting mental health through higher perceived bluespace, restorative quality, and physical activity; and another engendering mental ill‐health through higher noise exposure and annoyance. Conclusions: We found evidence that having more greenspace near the residence supported mental health through several indirect pathways with serial components. Conversely, bluespace was not clearly associated with mental health. HighlightsGreen/bluespace might support mental health.We examined pathways underlying the effect.Increased greenspace supported mental health through indirect pathways.Bluespace was not clearly associated with mental health.

Iodine Nutrition in Bulgaria: Results from the National Strategy for Elimination of Iodine Deficiency Disorders in Bulgaria – Epidemiologic Studies on Risk Population Groups

The environment of the Balkan countries, including Bulgaria, is known for its low content of iodine. The iodine deficiency regions comprise 1/3 of the country territory. The first national program for control of iodine deficiency disorders (IDD) was introduced in Bulgaria in 1958; however, iodine prophylaxis was interrupted during the period of market-oriented reforms. The strategies for prevention and control of IDD in Bulgaria were updated in 1994 and universal salt iodization and iodine supplementation for the population groups at risk were introduced. Despite the results achieved the level of information in the population concerning the health consequences of iodine deficiency and the purpose of applied prophylaxis with salt iodine fortification is not yet sufficient. Therefore, in the national action plan “Food and Nutrition, 2005–2010” an instruction on iodine deficiency problems for general practitioners, health education lessons in schools, and information for the whole population through appropriate informative flyers is included. The results from the studies of iodine status of schoolchildren living in urban and rural areas in south Bulgaria indicated that about 50% of them had optimal iodine nutrition. Statistically significant differences were found in some of the subgroups with different iodine status, which underlines the importance of socioeconomic status and the living standard of the population for the development of IDD. An unfavorable result found in these surveys was that a significant number of the children, schoolchildren and pregnant women had more than adequate or excessive iodine intake. In a population characterized by long-standing iodine deficiency and a rapid increase in iodine intake, there is a risk of iodine-induced hyperthyroidism.

Public health: the science of promoting health

Public health is “the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals” (Winslow 1920). The United Nations’ World Health Organization defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.” (WHO 1946). Public health plays an important role in disease prevention efforts in both the developing world and in developed countries through local health systems and through international non-governmental organizations. Today, most governments recognize the importance of public health programs in reducing the incidence of disease, disability, and the effects of aging, although public health generally receives significantly less government funding compared to medicine. This issue of the Journal of Public Health covers a broad range of current topics in public health; among them are the tobacco-related health problems. A number of scientific and medical evidence shows that the dangers associated with secondhand smoking are extremely serious and relevant. Many countries have implemented a full publicsmoking ban to protect the health of their citizens from the harmful effects of passive smoke. Balachandar et al. study the frequency of chromosomal aberrations among infertile male subjects in comparison to control subjects with the same pack-years and their offsprings (secondhand smokers). The authors identify higher degrees of chromosomal damage in infertile subjects compared to control smokers but Y chromosomal alterations were found in both subjects and offsprings. This finding is a distress signal for possible transmission of the current health-related problems of smokers into the next generation. Health hazards of obesity and being overweight are a growing concern for public health professionals. A study by Bau al. points out that postmenarche girls are more than twice as likely to be overweight and/or abdominally overweight as premenarche girls within the same age group. Therefore, not only the age but also the progress of maturation is important for assessing the growth and health of adolescents. For a long time obesity was considered a problem in high-income countries but now it is also growing in lowincome regions, especially in urban settings (James et al. 2001). A cohort study by Shiying Fu et al. examines the influence of central obesity indexed by waist circumference to height ratio (W/H) on the adverse levels of metabolic syndrome among adults with normal weight in a lowincome rural Chinese region. Groups adjusted for age and sex with W/H index below 0.5 have significantly different levels of blood pressure, triglycerides, high-density lipoprotein-bound cholesterol, and glucose compared to the group with W/H index above 0.5. The findings from the study underscore the importance of the utility of W/H as a measure of abdominal fat accumulation in predicting metabolic syndrome even among individuals with normal weight in terms of body mass index. During the last years, a dramatic increase in the average lifespan is widely credited to public health achievements such as vaccination programs and control P. D. Gatseva (*) Department of Hygiene, Ecology and Epidemiology, Medical University, 15a Vassil Aprilov Street, 4002 Plovdiv, Bulgaria e-mail: gatseva_p@mail.bg

Lower Noise Annoyance Associated with GIS-Derived Greenspace: Pathways through Perceived Greenspace and Residential Noise

Growing amounts of evidence support an association between self-reported greenspace near the home and lower noise annoyance; however, objectively defined greenspace has rarely been considered. In the present study, we tested the association between objective measures of greenspace and noise annoyance, with a focus on underpinning pathways through noise level and perceived greenspace. We sampled 720 students aged 18 to 35 years from the city of Plovdiv, Bulgaria. Objective greenspace was defined by several Geographic Information System (GIS)-derived metrics: Normalized Difference Vegetation Index (NDVI), tree cover density, percentage of green space in circular buffers of 100, 300 and 500 m, and the Euclidean distance to the nearest structured green space. Perceived greenspace was defined by the mean of responses to five items asking about its quantity, accessibility, visibility, usage, and quality. We assessed noise annoyance due to transportation and other neighborhood noise sources and daytime noise level (Lday) at the residence. Tests of the parallel mediation models showed that higher NDVI and percentage of green space in all buffers were associated with lower noise annoyance, whereas for higher tree cover this association was observed only in the 100 m buffer zone. In addition, the effects of NDVI and percentage of green space were mediated by higher perceived greenspace and lower Lday. In the case of tree cover, only perceived greenspace was a mediator. Our findings suggest that the potential for greenspace to reduce noise annoyance extends beyond noise abatement. Applying a combination of GIS-derived and perceptual measures should enable researchers to better tap individuals’ experience of residential greenspace and noise.

Pathways linking residential noise and air pollution to mental ill-health in young adults

Background: Recent years have seen growing, but still tentative, evidence of the potential associations of environmental noise and air pollution with mental disorders. In the present study, we aimed to examine the associations between residential noise and air pollution exposures and general mental health in young adults with a focus on underlying processes Methods: We sampled 720 students (18–35 years) from one university in the city of Plovdiv, Bulgaria. Residential noise (LAeq; day equivalent noise level) and air pollution (NO2) were assessed at participants residential address by land use regression models. General mental health was measured with a short form of the General Health Questionnaire (GHQ). The following putative mediators were considered: annoyance from environmental pollution, sleep disturbance, restorative quality of the neighborhood, neighborhood social cohesion, and commuting/leisure time physical activity. Structural equation modeling was used to analyze the theoretically‐indicated interplay between exposures, mediators, and GHQ. Results: We observed an association between higher LAeq and GHQ, in which environmental annoyance and neighborhood restorative quality emerged as key mediators. First, LAeq was associated with higher annoyance, and through it with lower restorative quality, and then in turn with lower physical activity, and thus with higher GHQ. Simultaneously, higher annoyance was associated with higher sleep disturbance, and thereby with higher GHQ. NO2 had no overall association with GHQ, but it was indirectly associated with it through higher annoyance, lower restorative quality, and lower physical activity working in serial. Conclusion: We found evidence that increased residential noise was related to mental ill‐health through several indirect pathways. Air pollution was associated with mental health only indirectly. HighlightsA model with multiple pathways was tested.Daytime noise was related to poor mental health.Air pollution had only an indirect effect.Key mediators: annoyance and neighborhood restorative quality.

Association between community noise and adiposity in patients with cardiovascular disease

Introduction: This study aimed to explore the effect of community noise on body mass index (BMI) and waist circumference (WC) in patients with cardiovascular disease (CVD). Materials and Methods: A representative sample of 132 patients from three tertiary hospitals in the city of Plovdiv, Bulgaria was collected. Anthropometric measurements were linked to global noise annoyance (GNA) based on different residential noise annoyances, day–evening–night (Lden), and nighttime (Lnight) road traffic noise exposure. Noise map Lden and Lnight were determined at the living room and bedroom façades, respectively, and further corrected to indoor exposure based on the window-opening frequency and soundproofing insulation. Results and Discussion: Results showed that BMI and WC increased (non-significantly) per 5 dB. The effect of indoor noise was stronger in comparison with that of outdoor noise. For indoor Lden, the effect was more pronounced in men, those with diabetes, family history of diabetes, high noise sensitivity, using solid fuel/gas for domestic heating/cooking, and living on the first floor. As regards indoor Lnight, its effect was more pronounced in those with low socioeconomic status, hearing loss, and using solid fuel/gas for domestic heating/cooking. GNA was associated with lower BMI and WC. Conclusion: Road traffic noise was associated with an increase in adiposity in some potentially vulnerable patients with CVD.