burden of myocardial infarction attributable to road traffic noise a pilot study in belgrade

Burden of myocardial infarction attributable to road-traffic noise: A pilot study in Belgrade Katarina Paunović, Goran Belojević Institute of Hygiene and Medical Ecology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia Abstract The aim of this pilot study was to calculate the disability-adjusted life years (DALY) as a quantification of the burden of myocardial infarction (MI) attributable to road-traffic noise in Belgrade, Serbia Exposure to road-traffic noise was estimated on a sample of almost 6000 adult inhabitants living in the central municipality Stari Grad in Belgrade, Serbia Each participant was assigned to daytime noise levels for 16 h exposure measured on the street of current residence Population-attributable fraction of MI due to road-traffic noise was calculated based on the distribution of the population in different noise exposure categories and the respective relative risk of MI compared to the reference level DALYs due to noise-related MI were calculated as the sum of years of life lost and years with disability The contribution of road traffic noise to the occurrence of MI for the population of the municipality Stari Grad in Belgrade equals 2.518% Total DALY for MI due to road-traffic noise results in 176 years, that is, 115 years for men and 61 years for women When adjusted for the present size of the population in Belgrade, total DALY due to road-traffic noise equals 107 years/million inhabitants that is, 70/million inhabitants for men and 37/million inhabitants for women The burden of disease due to road-traffic noise in Belgrade is relatively small but noteworthy from the public health point of view Keywords: Disability-adjusted life years, myocardial infarction, noise, transportation, years of life lost, years lost due to disability Introduction place in these cities Until date, however, noise mapping of any city in Serbia is still at the planning stage Environmental noise presents a large public health problem in many countries Back in 2009, Serbia implemented the law on the protection from environmental noise,[1] harmonized with the European Union Directive 2002/49/EC relating to the assessment and management of environmental noise.[2] The law and its amendments oblige authorities to create noise maps for agglomerations above 250,000 inhabitants by June 30, 2015, as well as for agglomerations above 100,000 inhabitants by June 30, 2020.[1,3] At the same time, the estimated population of Serbia was 7,320,807 inhabitants.[4] The country is divided into 25 administrative regions; out of 25 regions are inhabited by more than 250,000 persons Within these administrative regions, the cities of Belgrade, Novi Sad, Kragujevac and Niš can be defined as urban agglomerations according to the directive 2002/49/EC Consequently, the first round of noise mapping should take Access this article online Quick Response Code: Website: www.noiseandhealth.org DOI: 10.4103/1463-1741.144415 PubMed ID: *** Noise & Health, November-December 2014, Volume 16:73, 374-379 Disability-adjusted life years (DALY) is a population-related indicator of the burden of disease, measuring the gap between current health status and an ideal health situation where the entire population lives to an advanced age, free of disease and disability.[5] DALY is calculated as the sum of the number of life years lost due to premature death (years of life lost [YLL]) and the number of years lived with disability due to a given disease or condition or its consequences (years lost due to disability [YLD]).[5,6] One DALY can be interpreted as one lost year of healthy life Key advantages of DALY are that it combines the quantity of life (premature death) with the quality of life (time spent with disability) and that it helps compare various risk factors and diseases with the burden of disease.[7] Global and regional burden of disease was estimated for many diseases,[8] as well as for some environmental factors, including unsafe water, sanitation and hygiene,[9,10] indoor smoke,[11] and outdoor air pollution.[12] As for environmental noise, World Health Organization (WHO) has recently published two guidelines for risk assessment and quantification of the burden of disease in relation to noise exposure.[5,13] 374 Paunović and Belojević: Noise-related burden of disease Given the lack of official estimations of the burden of disease from noise in Serbia, we have decided to undertake a pilot study in a small urban area, which may initiate similar largescale assessments in the selected urban agglomerations The aim of this study was to calculate DALY as a quantification of the burden of myocardial infarction (MI) attributable to road-traffic noise in Belgrade, Serbia Facing the lack of noise maps for Belgrade we had to extrapolate noise exposure in a single urban municipality of Stari Grad to the whole population of Belgrade Methods Noise exposure assessment Calculation of the population-attributable fraction for myocardial infarction due to road-traffic noise The population-attributable fraction (PAF) was calculated based on the distribution of the population in different exposure categories and the respective relative incidence of disease The method was adapted from the guidelines for the estimation of the burden of disease from environmental noise proposed by the WHO.[5,14] First, the exposure-response function [Equation 1] was applied to calculate odds ratios (OR) for the occurrence of MI in relation to Lday16h daytime noise.[5,14,15] The OR is an estimate of the population relative risk (RR) Exposure to road-traffic noise was estimated on a sample of almost 6000 inhabitants living in a single municipality of Belgrade, Serbia The down-town municipality of Stari Grad is characterized by the predominance of road traffic over other sources of urban noise According to census data, the municipality population is about 55,000 adults Adult residents of every 10th apartment in all streets were approached by distributing questionnaires to post boxes inside the buildings according to the list of dwellers The sampling was conducted from 2004 to 2009 In total, 11,420 questionnaires were distributed, and 6049 were filled out and returned (response rate 52.9%) Persons who failed to report their current address or basic socio-demographic data (n = 188) were excluded from the study The final sample, therefore, comprised 5861 participants, 2598 men, and 3263 women aged 42.9 ± 17.9 years OR = 1.63 – 0.000613 (Lday16h)2 + 0.00000736 (Lday16h)3  (Equation 1) Noise levels were measured in the middle of 118 streets of this municipality during September-October 2008 A handheld noise level analyzer type 2250 Brüel and Kjær was used, according to recommendations of the International Standard Organization for the measurement of community noise (ISO, 1982) Noise measurements were performed on working days Equivalent noise levels (Leq) were measured in two intervals during the daytime (between and 10 am, and between and pm), and in one evening interval (between and pm) Noise level meter was positioned on the pavement by the road; the time interval of each measurement was 15 min; the speed of sampling was 10/s, with 9000 samples collected per measurement at one site From the obtained Leq levels, the composite 16-h daytime noise level (Leq16h [decibel – the unit of A-weighted sound pressure level [dBA]) was calculated for each street Each participant was assigned to daytime Leq16h values measured at the street of current residence Calculation of disability-adjusted life years The obtained 16-h daytime noise levels were divided into five exposure categories: 75.0 dBA The proportion of participants belonging to each exposure category was calculated 375 Second, the attributable risk percentage (AR%) among the population exposed to a given noise level range was calculated according to the Equation 2, based on the OR (RRs) for all exposure categories AR% = [(RR−1)/RR]100 [%] (Equation 2) Third, PAF for MI due to road-traffic noise was calculated from the proportion of the population in each exposure category i (Pi) and the RR (RRi) at each exposure category i compared to reference level, according to Equation 3.[5,14] PAF = [Σ (Pi RRi) −1]/ Σ (Pi RRi) (Equation 3) Newly diagnosed cases and deaths from MI in Belgrade in 2010 by gender and age groups were obtained from the Serbian Acute Coronary Syndrome Registry.[16] In 2010, the total number of newly diagnosed cases of MI was 4083 (2536 men and 1547 women), and the total number of deaths due to MI was 1189 (699 men and 490 women).[16] First, total YLL were calculated by multiplying the number of deaths from MI for each age category (N) with the standard life expectancy at age of death, or average loss of life years per death due to MI (L) [Equation 4].[6] YLL = N L (Equation 4) In order to calculate the average years lost due to premature death from MI, we relied on the average life expectancy of the population in Serbia, reported by the Institute of Public Health of the Republic of Serbia.[4] The estimated life expectancy in Belgrade is 71.89 years for men, and 77.18 years for women Therefore, total YLL were calculated for men and women separately Furthermore, YLL due to road-traffic noise were calculated by multiplying total YLL with PAF Noise & Health, November-December 2014, Volume 16 Paunović and Belojević: Noise-related burden of disease Second, YLD due to road-traffic noise were calculated by multiplying the number of non-fatal cases of MI attributable to road-traffic noise (I) with disability weights (DW) and average duration of disability (L), according to Equation 5.[6] YLD = I DW L (Equation 5) The number of non-fatal cases attributable to road-traffic noise (I) was calculated by multiplying total number of nonfatal cases of MI with PAF Total number of non-fatal cases of MI was obtained by subtracting the number of deaths from MI from the number of newly diagnosed cases from MI, in order to avoid double counting of cases Disability weight is an index in between and indicating the severity of the disability associated with the health condition For the purposes of this study, a DW of 0.405 was applied, in accordance to WHO guidelines.[5] Average duration of disability was fixed at 1, to calculate data for each year of life Finally, to estimate the DALYs lost due to noise-related MI in Belgrade, YLL and years with disability due to road-traffic noise were added, according to the following formula [Equation 6].[5,6-14] DALY = YLL + YLD (Equation 6) Taking into account the size of Belgrade population in 2010,[16] the obtained DALY values were further adjusted per million inhabitants Results Table presents the estimated exposure to road-traffic noise, RR and attributable fraction for MI The study reveals that almost 65% of the population of Stari Grad is exposed to noise levels