Epidemiologi Kesehatan Kerja dan Lingkungan Aria Gusti
Learning Objective • The student should be able to discuss exposure assessment that are relevant to assessing environmental or occupational hazards in epidemiology. • The student should be able to explain the strengths and limitations of epidemiological study designs for evaluating environmental or occupational hazards. • The student should be able to identify study designs that are especially relevant to studying environmental or occupational hazards, and explain the rationale for these study designs
Environmental Health “Whoever wishes to investigate medicine properly should proceed thus: When he comes into a strange city, he ought to consider its situation, how it lies to the wind and the sun, and consider the waters the people use. For if he knows these things well, he cannot miss knowing the diseases peculiar to the place." Hippocrates (340 B.C.)
Definition: ‘Environment’ • ‘…[Segala] segala sesuatu yang diluar diri manusia sebagai host. [Itu] dapat dipilah menjadi lingkungan fisika, biologi, sosial budaya dimana sebagian atau seluruhnya dapat mempengaruhi status kesehatan di dalam populasi.’ (WHO, 1995)
Definition: Environmental Epidemiology • “Ilmu yang mempelajari efek dari faktor fisika, biologi dan kimia di lingkungan eksternal terhadap kesehatan manusia, dalam artian luas. • Dengan menguji secara spesifik populasi atau komunitas terpapar dengan lingkungan ambien berbeda, adalah upaya untuk mempertegas hubungan antara faktor fisika, kimia dan biologi dengan kesehatan manusia”. National Research Council, USA (1991)
Definition: Environmental Epidemiology • “adalah studi atau cabang keilmuan yang mempelajari faktor-faktor lingkungan yang mempengaruhi timbulnya kejadian suatu penyakit, dengan cara mempelajari dan mengukur dinamika hubungan interaktif antara penduduk dengan lingkungan yang memiliki potensi bahaya pada suatu waktu dan kawasan tertentu, untuk upaya promotif lainnya (Achmadi, 1991).
Individual Risk and Population Rate • Individual: Dose
• Population: Exposure
Response
Risk: likelihood of effect in the individual based on the dose
Risk: proportion Response
of persons with outcome based on the exposure
Epidemiologi Lingkungan A. Features and Challenges
Classic Environmental Epidemiology Studies • Cholera in London and its relationship to water supply location for different households (Snow, 1854) • Nuclear bombs at Hiroshima and Nagasaki - studies of radiation effects among bomb survivors • Severe air pollution in London led to a epidemic of deaths from heart and lung disease (1952)
Classic Environmental Epidemiology Studies Number of House
Cholera Deadths
Deaths per 10.000 house
Southwark & Vauxhall Co
40.046
1.263
315
Lambeth & co
26.107
98
37
Rest of London
256.423
1.422
59
Water Supply
Classic Environmental Epidemiology Studies • "Minamata disease” – mengkonsumsi ikan yang terkontaminasi dengan methyl mercury • "Itai-Itai disease” – mengkonsumsi beras yang terkontaminasi dengan cadmium • Legionnaires' disease – penyakit infeksi yang menyebar melalui sistem ventilasi
Diseases Linked with Environmental Factors Disease Group Subgroup
Environmental factor
Gastrointestinal Diarrheal disease Cancer Lung Blood cells Soft tissue Liver Urinary tract Respiratory Asthma Bronchitis Emphysema Reproductive Malformations Abortions Low birth weight Neurological Development Transmission
Bacteria and viruses in water/water Tobacco smoke, metals, radiation Hydrocarbons, radiation Hydrocarbons, herbicides Hydrocarbons Certain chemical compounds Climate, particles, ozone Particulate, sulfates Smoke, sulfates, ozone Chemical mixtures, solvents Metals, hydrocarbons Tobacco smoke, chemical mixtures Lead Lead, organic solvents
Epidemiologi Lingkungan
features and challenges • Mengidentifikasi kerangka sampling dan populasi studi yang cocok di komunitas • Exposure assessment • Multiple hazards and multi-level risks • Hazards sering tidak bisa dikontrol secara individual dan mungkin tidak tercatat • Small effects pada populasi yang besar bisa menjadi bermakna, tapi sulit untuk dideteksi
Population Attributable Risk: Effect of Relative Risk and Proportion Exposed Small relative risk, Large exposed population
Relative Risk
Large relative risk, small exposed population
0% 25% Proportion Exposed
0%
80% Proportion Exposed
Population
Major Steps in Conducting Epidemiological Study • Establish objectives and hypotheses • Determine study design – Establish sampling frame • Select study population • Measure relevant variables Exposures Health Outcomes • Compare populations
Typical Sampling Frames for Environmental Studies • Community studies – Census (select all persons in population – jarang digunakan) – Multi-level cluster sample (e.g., all households on selected blocks) • Schools, workplaces, primary health care, community groups • Case-control studies – Cases from registry or hospitals; controls by random digit dialing
Determining Exposure Status • Existing environmental data • Questionnaires – Recalled exposures – Time-activity patterns • Environmental monitoring – Area sampling, personal monitoring • Examination – Laboratory tests for biological markers
• Question ?
