Age-sex specific and sequela-specific disability-adjusted life years (DALYs) due to dental caries preventable through water fluoridation: An assessment at the national and subnational levels in Iran, 2016

National and Subnational Trend of Dental Caries of Permanent Teeth in Iran, 1990-2017

OBJECTIVE

There are currently no integrated data on the trend of dental caries amongst distinct age groups in Iran. We aimed to assess the national and subnational trend of dental caries of permanent teeth in Iran from 1990 to 2017.

METHODS

A literature search about dental caries and the decayed-missing-filled teeth index (DMFT) was performed in PubMed, Web of Science, Scopus, and 3 national databases (in Persian). All eligible national oral health surveys in these 28 years were included. We categorised and aggregated the DMFT values and their components based on age (5-year-based groups from 5 to 9 to 60+ years), sex, year, and province. The data for missing spots were estimated using the spatiotemporal Bayesian hierarchical model. We used the bootstrap method in multilevel models to predict the uncertainty interval (UI) of the modelled results.

RESULTS

Nationally, the all-ages mean DMFT increased by nearly 58.0% (6.8 [95% UI, 4.1-10.5] in 1990 to 10.8 [95% UI, 7.5-14.5] in 2017). Decayed teeth (DT) and missing teeth (MT) rose by 84.5% and 31.6% during this period, respectively. Filled teeth (FT) showed almost a 2.6-fold increase in the same period from 0.6 (95% UI, 0.01-1.6) in 1990 to 1.7 (95% UI, 0.6-2.8) in 2017. The proportion of DT and FT continuously increased in both sexes. In 2017, the highest DT, MT, and FT were estimated in the 25-29 (4.9 [95% UI, 2.5-7.2]), 60+ (21.5 [95% UI, 17.5-25.4]), and 35-39 (2.6 [95% UI, 1.3-4.0]) year age groups.

CONCLUSIONS

Caries of permanent dentition levies a growing burden on the Iranian population. Considering the continuous increase in caries during the 1990-2017 period, Iranian policymakers should pay heed to these findings and react more proactively to mitigate this perpetuating issue. Implementing nationwide interventions such as sugar consumption management should be encouraged to achieve sustainable outcomes in this regards.

Burden of injury due to occupational accidents and its spatiotemporal trend at the national and subnational levels in Iran, 2011-2018

PURPOSE

The spatiotemporal trend of the burden of injury due to occupational accidents in Iran, 2011-2018 were assessed at the national and subnational levels.

METHODS

The burden of occupational injury was estimated using three datasets of occupational injury data, the employed population, and duration and disability weight of injuries.

RESULTS

The disability-adjusted life years (DALYs), deaths, DALY rate, and death rate (per 100,000 workers) of occupational injury in Iran drastically decreased from 169,523, 2,280, 827, and 11 in 2011 to 86,235, 1,151, 362, and 5 in 2018, respectively. The DALY rates of occupational injury were significantly different by gender and age in a manner that the DALY rate of men was much higher than that of women and the DALY rates by age group in 2018 ranged from 98 for 50 y and over to 901 for 15-19 y. The shares of injury outcomes in the total DALYs in 2018 were as follows: 63.6% for fatal injuries, 17.4% for fracture, 7.9% for open wound, 7.3% for amputation, and 3.8% for other injuries. Over 83% of the DALYs was observed in three economic activity groups of construction, manufacturing, and community, social, and personal service activities. The three provinces with the highest DALY rates in 2018 were Markazi, West Azarbaijan, and East Azarbaijan, respectively.

CONCLUSION

Despite the decreasing temporal trend, the burden of occupational injury in Iran in 2018 was high. The high-risk groups and hot spot provinces should be taken into more consideration for further reduction of the injury burden.

Evaluation of occurrence of organic, inorganic, and microbial contaminants in bottled drinking water and comparison with international guidelines: a worldwide review

The aim of this study was to evaluate the levels of inorganic and organic substances as well as microbial contaminants in bottled drinking water on a global scale. The findings were compared to WHO guidelines, EPA standards, European Union (EU) directive, and standards drafted by International Bottled Water Association (IBWA). Our review showed that 46% of studies focused on the organic contaminants, 25% on physicochemical parameters, 12% on trace elements, 7% on the microbial quality, and 10% on microplastics (MPs) and radionuclides elements. Overall, from the 54 studies focusing on organic contaminants (OCs) compounds, 11% of studies had higher OCs concentrations than the standard permissible limit. According to the obtained results from this review, several OCs, inorganic contaminants (IOCs), including CHCl3, CHBrCl2, DEHP, benzene, styrene, Ba, As, Hg, pb, Ag, F, NO3, and SO4 in bottled drinking water of some countries were higher than the international guidelines values that may cause risks for human health in a long period of time. Furthermore, some problematic contaminants with known or unknown health effects such as EDCs, DBP, AA, MPs, and some radionuclides (40K and 222Rn) lack maximum permissible values in bottled drinking water as stipulated by international guidelines. The risk index (HI) for OCs and IOCs (CHBrCl2, Ba, As, and Hg) was higher than 1 in adults and children, and the value of HI for CHCl3 in children was more than 1. Thus, further studies are required to have a better understanding of all contaminants levels in bottled drinking water.

Assessment of burden of disease induced by exposure to heavy metals through drinking water at national and subnational levels in Iran, 2019

The burden of disease attributable to exposure to heavy metals via drinking water in Iran (2019) was assessed at the national and regional levels. The non-carcinogenic risk, carcinogenic risk, and attributable burden of disease of heavy metals in drinking water were estimated in terms of hazard quotient (HQ), incremental lifetime cancer risk (ILCR), and disability-adjusted life year (DALY), respectively. The average drinking water concentrations of arsenic (As), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and nickel (Ni) in Iran were determined to be 2.3, 0.4, 12.1, 2.5, 0.7, and 19.7 μg/L, respectively, which were much lower than the standard values. The total average HQs of heavy metals in drinking water in the entire country, rural, and urban communities were 0.48, 0.65 and 0.45, respectively. At the national level, the average ILCRs of heavy metal in the entire country were in the following order: 1.06 × 10^-4 for As, 5.89 × 10^-5 for Cd, 2.05 × 10^-5 for Cr, and 3.76 × 10^-7 for Pb. The cancer cases, deaths, death rate (per 100,000 people), DALYs, and DALY rate (per 100,000 people) attributed to exposure to heavy metals in drinking water at the national level were estimated to be 213 (95% uncertainty interval: 180 to 254), 87 (73-104), 0.11 (0.09-0.13), 4642 (3793-5489), and 5.81 (4.75-6.87), respectively. The contributions of exposure to As, Cd, Cr, and Pb in the attributable burden of disease were 14.7%, 65.7%, 19.3%, and 0.2%, respectively. The regional distribution of the total attributable DALY rate for all heavy metals was as follows: Region 5> Region 4> Region 1> Region 3> Region 2. The investigation and improvement of relatively high exceedance of As levels in drinking water from the standard value, especially in Regions 5 and 3 as well as biomonitoring of heavy metals throughout the country were recommended.

Burden of disease induced by public overexposure to solar ultraviolet radiation (SUVR) at the national and subnational levels in Iran, 2005-2019

Estimating the burden of diseases induced by overexposure to solar ultraviolet radiation (SUVR) can help to prioritize environmental health interventions. The age-sex specific and cause-specific mortality and disability-adjusted life years (DALYs) attributable to overexposure to SUVR at the national and subnational levels in Iran, 2005-2019 were estimated. The burden of disease induced by overexposure to SUVR was quantified in four steps as follows: (1) estimating exposure to SUVR, (2) estimating total incidences and deaths of target causes, (3) assessing population attributable fractions of the target causes for the SUVR, and (4) calculating the attributable burden of disease. The attributable DALYs, deaths, age-standardized DALY rate, and age-standardized death rate at the national level were determined to be respectively 21896, 252, 42.59, and 0.56 in 2005 and were respectively changed to 28665, 377, 38.76, and 0.53 in 2019. The contributions of causes in the attributable DALYs at the national level were different by year and sex and for both sexes in 2019 were as follows: 46.15% for cataract, 20.36% for malignant skin melanoma, 16.07% for sunburn, 12.41% for squamous-cell carcinoma, and 5.01% for the other five causes. The contributions of population growth, population ageing, risk exposure, and risk-deleted DALY rate in the temporal variations of the attributable burden of disease in the country were +20.73%, +20.68%, +2.01%, and -12.51%. The highest and lowest provincial attributable age-standardized DALY rates in 2019 were observed in Fars (46.8) and Ardebil (32.7), respectively. The burden of disease induced by exposure to SUVR caused relatively low geographical inequality in health status in Iran. Due to increasing trends of the SUVR as well as the attributable burden of disease, the preventive interventions against the SUVR overexposure should be considered in the public health action plan all across the country.

National and subnational burden of disease attributable to occupational exposure to solar ultraviolet radiation (SUVR) in Iran, 2005-2019

Overexposure to solar ultraviolet radiation (SUVR) can cause skin and eye adverse effects for outdoor workers. In this study, the burden of disease induced by occupational exposure to SUVR and its spatiotemporal trend at national and sub-national levels in Iran, 2005-2019 were assessed. The attributable burden of disease was assessed using the following five datasets: (1) distribution of occupational exposure to SUVR, (2) total incidences and deaths of health outcomes of SUVR exposure, (3) population attributable fractions of the health outcomes of SUVR exposure, (4) age-gender distribution of outdoor workers, and (5) disability-adjusted life year (DALY) calculation constants. During 2005-2019, the attributable DALYs increased from 2442 to 2907 and the attributable DALY rate (per 100,000 workers) slightly decreased from 11.94 to 11.91. The share of YLL in the attributable burden of disease was in the range of 43%-46%. Out of nine causes, about 90% of the attributable burden of disease in 2019 was related to cataracts (29.9%), malignant skin melanoma (27.4%), squamous-cell carcinoma (18.6%), and sunburn (17.2%). During the study period, the attributable DALY rate in women increased by 60.95% (from 5.04 to 8.11) and in men decreased by 2.06% (from 13.03 to 12.76). The total attributable DALYs and DALY rate rose by age during 2005-2019. The contributions of population growth, risk-deleted DALY rates, exposure risk, and population age structure in temporal changes of the attributable burden of disease were 19.27%, 9.13%, -1.35%, and -14.8%, respectively. The three highest attributable DALY rates in 2019 were observed in South Khorasan (21.28), Chahar Mahal and Bakhtiari (17.42), and Kordestan (17.26), respectively. The preventive interventions against SUVR overexposure, regular screenings, and early treatments with an emphasis on occupations with continuous sun exposure and provinces with increasing attributable DALY rates should be considered in the occupational health action plan in the country.

Occurrence, migration and health risk of phthalates in tap water, barreled water and bottled water in Tianjin, China

This study was to investigate the occurrence, migration and health risk of phthalic acid esters (PAEs) in tap water, barreled water and bottled water in Tianjin, China. Six priority controlled PAEs were measured, among which the detection frequency of butyl benzyl phthalate (BBP), dibutyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) was 100%, while the others were not detected. The concentration of DEHP was higher than BBP and DBP in all the samples. The initial ∑₃PAEs concentrations in tap water, barreled water and bottled water were 2.409 ± 0.391 μg/L, 1.495 ± 0.213 μg/L and 1.963 ± 0.160 μg/L, respectively. Boiling tap water could reduce the PAEs content to an extent, but they increased significantly in hot tap water contacting with disposable plastic cups. The migration of PAEs in barreled water and bottled water were positively correlated with storage time and temperature, which could be described by exponential models. The hazard indexes of PAEs in different types of drinking water were very low. However, the human carcinogenic risks of DEHP will reach the maximum acceptable risk level of 10^-6 when bottled water is stored for 8.8 days at 40 °C, 7.7 days at 50 °C, or 6.1 days at 60 °C.

Spatial variation and health risk assessment of fluoride in drinking water in the Chongqing urban areas, China

Fluoride is an essential trace element for humans, and its deficiency or excess in the environment could lead to disease. To investigate the spatial distribution and health risk assessment of fluoride (F^-) in drinking water, 302 tap water samples from Chongqing urban areas, China, were collected to analyze F^- using an ion chromatograph. The results showed that (1) F^- concentration in drinking water ranged from 0.100 to 0.503 mg/L, with an average of 0.238 ± 0.045 mg/L. (2) The spatial autocorrelation analysis showed that high-low clusters were mostly located in Dadukou District and Beibei District, while low-low clusters were mainly in southern Banan District. (3) The fluoride average daily doses of children, teens and adults were 0.030, 0.029 and 0.031 mg/(kg day). (4) Hazard quotients of excessive fluoride (HQ_e) of children, teens and adults were 0.51 ± 09, 0.49 ± 0.09 and 0.52 ± 0.10, respectively (inferior to 1.00), whereas hazard quotients of inadequate fluoride (HQ_i) of those groups were 1.21 ± 0.26, 1.23 ± 0.26 and 1.15 ± 0.25, respectively (superior to 1.00). Therefore, average daily fluoride intake of residents with drinking water was inadequate. This could pose dental caries and osteoporosis threats for residents from Chongqing urban areas.

Two distinct mechanisms of fluoride enrichment and associated health risk in springs' water near an inactive volcano, southeast Iran

Groundwater fluoride contamination is a major issue of water pollution in the world with health hazards such as dental and skeletal fluorosis. This research focused on exposure to the high concentration of fluoride in the springs water in the Bazman volcanic area, southeast Iran. The combination of chemical/isotopic analysis, geochemical modeling, health risk assessment and multivariate statistical methods were applied to investigate the contamination and sources of fluoride in the samples. Groundwater samples were collected from cold and thermal springs. Major ions, fluoride, trace elements and stable isotopes δ¹⁸O and δD were measured in the samples using standard methods, ICP-MS and OA-ICOS, respectively. Fluoride content in springs varied from 0.5 to 3.75 mg/L with an average value of 1.66 mg/L. The highest fluoride concentrations were observed in the eastern cold springs while thermal springs showed the minimum fluoride contents. The majority of samples showed F contents higher than the calculated optimal concentration of fluoride (0.75 mg/L). Reaction of fluorite mineral with HCO₃ and replacement of F in clay minerals and metal oxy-hydroxides with OH^- in water were likely cause fluoride enrichment in the eastern springs. Whereas, in the western springs and thermal springs, origin of fluoride was related to weathering of muscovite, cryolite, apatite and fluoroapatite minerals. The δ¹⁸O and δ²H of the water samples displayed the impact on evaporation on fluoride enrichment in all spring water samples. The average value of contamination index (C_d) in the water samples was 1.94 categorizing medium risk level while springs S7, S8, S9 and S4 were above the threshold value of C_d index. The fluoride hazard quotient (HQ) showed that 25%, 44%, 56% and 0% of springs' water resources had high risk level for age group of adults, teenager, children and infants, respectively. Therefore, health risk of fluoride in drinking water resources were in the following order: children > teenager > adults > infants.

Age-sex specific and cause-specific health risk and burden of disease induced by exposure to trihalomethanes (THMs) and haloacetic acids (HAAs) from drinking water: An assessment in four urban communities of Bushehr Province, Iran, 2017

Health risk and burden of disease induced by exposure to trihalomethanes (THMs, four compounds) and haloacetic acids (HAAs, 5 compounds) from drinking water through ingestion, dermal absorption, and inhalation routes were assessed based on one-year water quality monitoring in four urban communities (Bandar Deylam, Borazjan, Bushehr, and Choghadak) of Bushehr Province, Iran. The total average concentrations of THMs and HAAs at all the communities level were determined to be 92.9 ± 43.7 and 70.6 ± 26.5 μg/L, respectively. The dominant components of the THMs and HAAs were determined to be tribromomethane (TBM, 41.6%) and monobromoacetic acid (MBAA, 60.8%), respectively. The average contributions of ingestion, dermal absorption, and inhalation routes in exposure to the chlorination by-products (CBPs) were respectively 65.0, 15.4, and 19.6%. The total average non-carcinogenic risk as the hazard index (HI) and incremental lifetime cancer risk (ILCR) of the CBPs at all the communities level were found to be 4.03 × 10^-1 and 3.16 × 10^-4, respectively. The total attributable deaths, death rate (per 100,000 people), age-weighted disability-adjusted life years (DALYs), and age-weighted DALY rate for all ages both sexes combined at all the communities level were estimated to be 1.0 (uncertainty interval: UI 95% 0.3 to 2.8), 0.27 (0.08-0.75), 30.8 (11.3-100.1), and 8.1 (3.0-26.4), respectively. The average contribution of mortality (years of life lost due to premature mortality: YLLs) in the attributable burden of disease was 94.7% (94.4-95.6). Although in most of cases the average levels of the CBPs were in the permissible range of Iranian standards for drinking water quality, the average values of ILCRs as well as attributable burden of disease were not acceptable (the ILCRs were higher than the boundary limit of 10^-5); therefore, implementation of interventions for reducing exposure to CBPs through drinking water especially in Kowsar Dam Water Treatment Plant is strictly recommended.

Oral and Dental Status of Lebanese and Syrian Refugees Living in Proximity to Deir Kanoun Ras El Ain Dump in Lebanon

Aims:

In this study, we aimed at investigating the oral and dental health conditions of Lebanese and Syrian refugees living in proximity to Deir Kanoun Ras El Ain dump whereby its leachates influx into a canal used for irrigation and drinking purposes.

Materials and Methods:

This observational study involved oral and dental examinations of 589 Lebanese and Syrian Refugees participants living in the three villages: Deir Kanoun Ras El Ain, Klayleh, and Smaiyeh. Differences in oral and dental examination results were analyzed between different villages, sexes, nationalities, and age groups. Correlation tests were conducted between dental fluorosis, staining, papilla swelling, and several sociodemographic factors.

Results:

Dental fluorosis, staining, and papilla swelling were the most prominent problems among total participants. The highest percentages of individuals with the studied diseases were shown to be in Klayleh village, among females, and individuals aged between 21 and 40 years. Significant associations were observed between dental fluorosis and nationality; between dental staining and gender, nationality, age, and smoking; as well as between papilla swelling and age, smoking, and diabetes.

Conclusions:

Our study investigated and highlighted the prevalence of several oral and dental diseases among Lebanese and Syrian inhabitants that are related to environmental, social, and economic determinants and not just by individual behaviors. It also showed gaps of oral and dental health knowledge that recommend implementing health systems that focus on preventing oral diseases.

Age-sex specific disability-adjusted life years (DALYs) attributable to elevated levels of fluoride in drinking water: A national and subnational study in Iran, 2017

National and subnational burden of disease attributable to elevated fluoride levels in drinking water apportioned by sex, age group, province, and community type in Iran, 2017 were quantified based on disability-adjusted life years (DALYs). The attributable burden of disease was estimated using four input data: (1) effect size of elevated drinking water fluoride levels for dental and skeletal fluorosis, (2) population distribution of drinking water fluoride levels, (3) the threshold levels of fluoride in drinking water for contribution in dental and skeletal fluorosis, and (4) age-sex distribution of population. The attributable burden of disease was only related to dental fluorosis, because the fluoride levels were lower than the threshold value for skeletal fluorosis (4.0 mg/L) in all of the cases. The national attributable prevalence (per 100,000 people), DALYs, and DALY rate in 2017 were calculated to be 60 (95% uncertainty interval 48-69), 3443 (1034-6940), and 4.31 (1.29-8.68), respectively. The national attributable burden of disease was not significantly different by sex, but was affected by age and community type in a manner that the highest DALY rate was related to the age group 10-14 y (6.06 [1.82-12.21]) and over 66% of the national attributable DALYs occurred in rural communities. The attributable burden of disease occurred only in 10 out of 31 provinces and about 94% of the attributable DALYs were concentrated in four provinces Fars (1967 [592-3964]), Bushehr (414 [124-836]), West Azarbaijan (400 [120-808]), and Hormozgan (377 [113-761]). Implementation of fluoride-safe drinking water supply schemes in the four leading provinces can prevent most of the national health losses and partly compensate the increasing trend of disease burden from oral conditions at the national level.

Health risk of phthalates in water environment: Occurrence in water resources, bottled water, and tap water, and burden of disease from exposure through drinking water in tehran, Iran

Occurrence of phthalates in water resources, bottled water, and tap water, and health risk of exposure to the phthalates through drinking water in Tehran, Iran, 2018 were studied. The six phthalates with the most health and environmental concerns, including di-(2-ethylhexyl) phthalate (DEHP), butyl benzyl phthalate (BBP), di-n-butyl phthalate (DBP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and di-n-octyl phthalate (DNOP) were monitored in drinking water and water resources. The average levels (±standard deviation: SD) of the total phthalates in drinking water from the water distribution system, bottled water, surface waters, and ground waters were determined to be 0.76 ± 0.19, 0.96 ± 0.10, 1.06 ± 0.23, and 0.77 ± 0.06 μg/L, respectively. The dominant compounds in the phthalates were DMP and DEHP causing a contribution to the total phthalate levels higher than 60% in all the water sources. The phthalate levels of drinking water significantly increased by contact of hot water with disposable plastic and paper cups and by sunlight exposure of bottled water (p value < 0.05). The hazard quotients (HQs) of DEHP, BBP, DBP, and DEP for all ages both sexes combined were determined to be 1.56 × 10^-4, 1.01 × 10^-5, 1.80 × 10^-5, and 1.29 × 10^-6, respectively that were much lower than the boundary value of 1.0. The disability-adjusted life years (DALYs) and DALY rate (per 100,000 people) attributable to DEHP intake through drinking water for all ages both sexes combined were estimated to be 6.385 (uncertainty interval: UI 95% 1.892 to 22.133), and 0.073 (0.022-0.255), respectively. The proportion of mortality in the attributable DALYs was over 96%. The attributable DALY rate exhibited no significant difference by sex, but was considerably affected by age in a manner that the DALY rates ranged from 0.052 (0.015-0.175) in the age group 65 y plus to 0.099 (0.026-0.304) in the age group 5 to 9 y. Both the carcinogenic and non-carcinogenic health risks of the phthalates in drinking water were considered to be very low. The results can also be of importance in terms of developing frameworks to expand the domain of burden of disease study to the other environmental risks.

Evaluation of vascular and kidney injury biomarkers in Mexican children exposed to inorganic fluoride

Exposure to inorganic fluoride (F) has been implicated in cardiovascular and kidney dysfunction mainly in adult populations. However, limited epidemiological information from susceptible populations, such as children, is available. In this study we evaluated the relationship of F exposure with some vascular and kidney injury biomarkers in children. A cross-sectional study was conducted in 374 Mexican schoolchildren. Dental fluorosis and F concentrations in the water and urine were evaluated. The glomerular filtration rate (eGFR) and the urinary concentrations of kidney injury molecule 1 (KIM-1) and cystatin-C (uCys-C) were examined to assess kidney injury. The carotid intima media thickness (cIMT) and serum concentrations of vascular adhesion molecule 1 (VCAM-1), intracellular adhesion molecule 1 (ICAM-1), endothelin 1(ET-1) and cystatin-C (sCys-C) were measured to assess vascular alterations. High proportions of children exposed to F were observed (79.7% above 1.2 ppm F in urine) even in the low water F exposure regions, which suggested additional sources of F exposure. In robust multiple linear regression models, urinary F was positively associated with eGFR (β = 1.3, p = 0.015), uCys-C (β = -8.5, p = 0.043), VCAM-1 (β = 111.1, p = 0.019), ICAM-1 (β = 57, p = 0.032) and cIMT (β = 0.01, p = 0.032). An inverse association was observed with uCys-C (β = -8.5, p = 0.043) and sCys-C (β = -9.6, p = 0.021), and no significant associations with ET-1 (β = 0.069, p = 0.074) and KIM-1 (β = 29.1, p = 0.212) were found. Our findings revealed inconclusive results regarding F exposure and kidney injury. However, these results suggest that F exposure is related to early vascular alterations, which may increase the susceptibility of cardiovascular diseases in adult life.