Are the elements zinc, copper, magnesium, and rubidium related to nutrition and iodine deficiency in pregnant Bulgarian women from iodine deficient region?

OBJECTIVE: Trace elements are essential for the biochemistry of the cell. Their reference values have been found to differ considerably in pregnant women stratified by age, place of residence, anthropometric status, and length of pregnancy. In optimal amounts, these elements reduce the risk of pregnancy complications. Subclinical hypothyroidism in pregnancy is associated with adverse maternal and neonatal outcomes. The aim of the study was to determine the effects of zinc (Zn), copper (Cu), magnesium (Mg), and rubidium (Rb) on pregnant women in an iodine deficiency region and find the relationship with the thyroid status and nutrition. METHODS: We evaluated the iodine status of 61 healthy pregnant women from an iodine deficient region in Bulgaria. Thyroid stimulating hormone (TSH) and thyroxin free (FT4) levels were measured using ELISA. RESULTS: We found elevated levels of copper that differed the most between the first and second trimesters; Cu and TSH were found to be positively correlated (р < 0.05). Lower Cu levels were found in pregnant women consuming pulses more than 2-3 times a week (р = 0.033). The women consuming fish more than 2-3 times a week had higher levels of Rb. We found a pronounced iodine deficiency in more than half of the examined women in the first to third trimesters, without any effect of pregnancy on the ioduria (р=0.834). All second and third trimester cases were associated with severe ioduria (< 150 µg/L). CONCLUSION: The high Cu levels were associated with subclinical hypothyroidism (SCH) and less pulse consumption during pregnancy in an iodine deficiency endemic area. SCH was found in 24% of the pregnant women in such an area while in 13% of them SCH had progressed to overt hypothyroidism.

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 participant's 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.

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.

Community Noise Exposure and its Effect on Blood Pressure and Renal Function in Patients with Hypertension and Cardiovascular Disease.

BACKGROUND: Road traffic noise (RTN) is a risk factor for cardiovascular disease (CVD) and hypertension; however, few studies have looked into its association with blood pressure (BP) and renal function in patients with prior CVD. AIM: This study aimed to explore the effect of residential RTN exposure on BP and renal function in patients with CVD from Plovdiv Province. MATERIALS AND METHODS: We included 217 patients with ischemic heart disease and/or hypertension from three tertiary hospitals in the city of Plovdiv (March - May 2016). Patients' medical history, medical documentation, and medication regimen were reviewed, and blood pressure and anthropometric measurements were taken. Blood samples were analyzed for creatinine, total cholesterol, and blood glucose. Participants also filled a questionnaire. Glomerular filtration rate was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. All participants were asked about their annoyance by different noise sources at home, and those living in the city of Plovdiv (n = 132) were assigned noise map Lden and Lnight exposure. The effects of noise exposure on systolic blood pressure (SBP), diastolic blood pressure (DBP), and estimated glomerular filtration rate (eGFR) were explored using mixed linear models. RESULTS: Traffic noise annoyance was associated with higher SBP in the total sample. The other noise indicators were associated with non-significant elevation in SBP and reduction in eGFR. The effect of Lden was more pronounced in patients with prior ischemic heart disease/stroke, diabetes, obesity, not taking Ca-channel blockers, and using solid fuel/gas at home. Lnight had stronger effect among those not taking statins, sleeping in a bedroom with noisy façade, having a living room with quiet façade, and spending more time at home. The increase in Lden was associated with a significant decrease in eGFR among men, patients with ischemic heart disease/stroke, and those exposed to lower air pollution. Regarding Lnight, there was significant effect modification by gender, diabetes, obesity, and time spent at home. In some subgroups, the effect of RTN was statistically significant. CONCLUSIONS: Given that generic risk factors for poor progression of cardiovascular diseases cannot be controlled sufficiently at individual level, environmental interventions to reduce residential noise exposure might result in some improvement in the management of blood pressure and kidney function in patients with CVD.

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.

Effect of Nitrates, Thiocyanates and Selenium on the Iron and Iodine Status of Postpartum Women.

AIM: To find correlations between high thiocyanate and nitrate levels and low selenium levels and the indicators of the iodine and iron status of postpartum women. MATERIALS AND METHODS: The study included 41 mothers aged 26.4±5.9 yrs from Asenovgrad and nearby villages. Urinary iodine was determined by the Sandell-Kolthoff reaction and thiocyanate - by the interaction of these ions with acidic solution of KMnO4; for serum nitrates we used the colorimetric method; serum selenium was assessed by electro-thermal atomic-absorption spectrophotometry; thyroxin (FT4), the thyroid stimulating hormone (TSH), serum ferritin (SF), and serum transferrin receptor (sTfR) were determined using ELISA; Hb levels were determined by hematology analyzer. RESULTS: Assessing the iodine status, we found a negative correlation between the levels of iodine and thiocyanates in urine (R=-0.717, р<0.0001), a positive correlation between nitrates and TSH (R=0.487, р=0.003) and a negative correlation between nitrates and FT4 (R=-0.312, р=0.06). For the iron status, we found a negative correlation between nitrates and SF (R=-0.429, р=0.009) and between nitrates and Hb (R=-0.383, р=0.021). The Mann-Whitney U-test showed that in women with nitrate levels higher than the mean value there was low FT4 level (р=0.06), high TSH level (р=0.013), low Hb concentration (р=0.061) and low SF concentration (р=0.005). The combined effects of environmental factors (elevated nitrate levels and low selenium level) on the iodine and iron status are manifested by low concentrations of FT4 (р=0.033), Hb (р=0.06) and SF (р=0.05) and high level of TSH (р=0.05). In conclusion, we found that environmental factors, especially when combined, have a negative impact on the iron and iodine status of females.

Effect of Thiocyanate on Iodine Status of Pregnant Women.

The aim of this study was to assess the thyroid status of pregnant women on the basis of biochemical indicators and to evaluate the potential risk of developing iodine deficiency as a result of tobacco smoke exposure by assessing the association between urinary thiocyanate levels and the manifestation of iodine deficiency. The study included 219 pregnant women from the town of Plovdiv and Plovdiv District in Southern Bulgaria. The levels of urinary iodine, thyroid-stimulating hormone (TSH), free thyroxine (FT4), and urinary thiocyanate as indicators of tobacco smoke exposure were measured. Most of the pregnant women (60.1 %) were found to have iodine deficiency, 10.6 % of them had TSH values greater than 4 mIU/L, and 16.4 % had FT4 below 9 pmol/L. There were negative correlations between urinary iodine levels and thiocyanate/creatinine ratio (R = -0.148, р = 0.034) and between thiocyanate/creatinine ratio and FT4 (R = -0.379, p < 0.0001); thiocyanate/creatinine ratio and serum TSH were positively correlated (R = 0.169, p = 0.019). Logistic regression analysis showed that pregnant women in whom the thiocyanate/creatinine ratio was greater than the median value of 3.57 mg/g had a 3.882-fold higher risk of developing iodine deficiency (urinary iodine <150 µg/L) than the pregnant women with lower thiocyanate levels (OR = 3.882, 95 % CI 1.402-10.751, p = 0.009). Higher levels of urinary thiocyanate were found in women exposed to tobacco smoke, and quantification of these ions in urine provided a fast non-invasive method to monitor thiocyanate load. Due to the competitive inhibition of iodine intake by thiocyanates, their levels should be carefully monitored, especially in cases of severe iodine deficiency.

The Role of Eating Habits on the Iron Status of Pregnant Women.

OBJECTIVE: This study highlights the relationship between some eating habits and iron status during pregnancy. SUBJECTS: The study included 219 healthy pregnant women aged 27.6 ± 5.7 years from southern Bulgaria. METHODS: Subjects' iron status was assessed on the basis of the following iron indicators: hemoglobin (Hb), serum ferritin (SF), serum transferrin receptor (sTfR), and body iron index (mg/kg). RESULTS: Severe anemia among the women from southern Bulgaria was not observed. Advanced pregnancy and some eating habits are factors that deteriorate iron status. Women who had consumed fish at least 3 times a week had lower levels of sTfR (р = 0.008), higher levels of SF (р = 0.05), and lower levels of body iron (р = 0.018). Frequent legume consumption was related to increased levels of sTfR (р = 0.036). Pregnant women with a high frequency of coffee consumption had lower values of body iron (р < 0.0001). Women who had consumed cow's milk at least 3 times a week had lower levels of SF (р = 0.026) and body iron (р = 0.042). CONCLUSIONS: Regular consumption of fish and legumes, rarely drinking coffee, and milk consumption during the intervals between food intake are conditions for optimization of iron status during pregnancy.

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.

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 iodinedeficiency 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.

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 microg/l) and nonexposed (202.50 microg/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.