Heat stress and well-being impact
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Heat stress and well-being impact
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Heat stress and well-being impact
- 1. “HEAT STRESS, HEALTH AND WELLBEING: FINDINGS FROM A LARGE NATIONAL COHORT OF THAI ADULTS” Benjawan Tawatsupa1 , Vasoontara Yiengprugsawan2, Tord Kjellstrom3, Sam-ang Seubsman4, Adrian Sleigh2 Department of Health, MOPH, Thailand 2 National Centre for Epidemiology and Population Health, ANU, Australia, 3 Centre for Global Health Research, Umeå University, Sweden, 4 Nonthaburi, School of Human Ecology, Sukhothai Thammathirat Open University, Thailand, 1 Area 5: Social, Environmental and Cultural Issues in Health Promotion 26 August 2013
- 2. Heat stress in Thailand Tropical developing country: 65 M population Rapid urbanization: 40% in urban areas (60% in 2030) High average temperature: 28-30 °C High relative humidity: 80-90% Rising temperature By 0.74°C (from 1950 to 2007) (Limjirakan, 2008) Annual average of daily maximum temperature 1980-2090 Source: SEA START RC, 2009 2
- 3. Objective: To examine the association between heat stress interference with daily activities and health & well-being Daily activities: Health & wellbeing impacts Sleeping Work Physical health: Energy level Daily travel Housework Exercise Climate Change Heat Stress Human exposure Health Impacts Socioeconomic status & Individual behaviour (age, sex, marital status, work status, education, income, urban-rural residence, exercise, housework, hours of sleep, BMI, smoking , and drinking) Mental Health: Emotional problems Well-being Overall life satisfaction
- 4. Methods Data from a large national Thai Cohort Study (TCS) of distance- learning open-university adult students aged 15-87 years in 2009 (N=60,569) Researching the health-risk transition in the Thai population (Sleigh et al, 2008) Cross-sectional study using multinomial logistic regression analysis and adjusting for a wide array of potential confounders For each health outcome, we report Odds Ratios (ORs) and 95% confidence intervals
- 5. Results Daily activities and heat interference category Daily activities N = 60,569 Heat interference (%) Not applicable* Never Sometimes Often Daily travel 3.0 33.7 25.8 37.5 Work 14.0 30.3 21.2 34.5 Housework 1.3 37.1 31.7 29.9 Sleeping 15.7 24.3 32.5 27.4 Exercise 0.8 43.1 30.1 25.9 *e.g. Use air conditioning
- 6. Health and wellbeing outcomes Energy level % Emotional problems % very much 14.9 not at all 11.3 quite a lot 44.0 slightly 48.4 some 32.0 moderately 25.8 a little or none 9.1 quite a lot/extremely 14.5 Overall life satisfaction (score ranged from 0-10) 9-10 very satisfied (highest) 37.6 8 (high) 28.8 6-7 (medium) 21.7 0-5 not very satisfied (low) 12.0 %
- 7. Adjusted Odds Ratios Association between heat interference with daily activities and low energy level Daily activities and heat interference category
- 8. Adjusted Odds Ratios Association between heat interference with daily activities and worse emotional problems Daily activities and heat interference category
- 9. Adjusted Odds Ratios Association between heat interference with daily activities and low life satisfaction Daily activities and heat interference category
- 10. Results Negative health and wellbeing outcomes associated with increasing frequency of heat stress interfering with daily activities. Worse emotional problems (adj.ORs 1.5 - 4.8) Low energy level (adj.ORs 1.3 - 2.9) Low life satisfaction (adj.ORs 1.1- 2.5) Adverse health outcomes were when heat stress interfered with Sleeping > daily travel > work > housework > exercise.
- 11. Limitations of this study 1) Cannot prove that adverse health outcomes occurred at the same time as the heat stress 2) Difficulties in interpreting causality between heat stress and health outcomes 3) we were not able to make direct measurement of environments or health outcomes - Must classify this study as preliminary in nature - Further studies are needed for more detailed direct observations 11
- 12. Conclusions In tropical Thailand, there already are substantial heat stress impacts on health and wellbeing Increasing temperatures from climate change as well as the growing urban population could significantly worsen the situation Results from this study point to the need for Improved public health surveillance & public awareness regarding the risks of heat stress in daily life
- 13. Thank you • National Centre for Epidemiology and Population Health, ANU, Australia • The Thai Cohort Study team (TCS) • The ‘High occupational temperature health and productivity suppression' programme (Hothaps) • Department of Health, Ministry of Public Health, Thailand 13
- 15. Background Heat loss "Heat stress" (ACGIH, 2008) Cooling by Evaporation Overall heat burden on the body from the combination of: H 2O Na+ Cl- H 2O Body heat generated Environmental sources − Air temperature − Humidity − Air movement − Radiation from the sun or hot surfaces/sources Clothing requirements H Heat gain From external heat source (Environment) Heat gain From internal heat source (Physical activity) 15
- 16. Heat stress interfered with daily travel Motorcyclists were using any shade they could find to get through one of the hottest days in April 2012. (Ainakul, Bangkok post 21/04/2012) 16
- 17. Research questions & Aim of study Why heat stress is interesting: 1) Worldwide interest but insufficient evidence on heat stress & health outcomes in Thailand 2) Heat stress is already a problem in tropical countries 3) Rising temperature may influence the future pattern of deaths or illness What we know: 1) Increasing temperature in Thailand already occurring (Limjirakan, 2008) 2) The effects of daily heat stress exposure can have a major influence on human daily activities but there is limited information regarding the impact on overall health and wellbeing What we do not know (research questions): 1) If temperature increases over time, are there any impacts of heat stress on overall health and wellbeing? Aim: To examine the association between heat stress interference with daily activities and health and wellbeing outcomes
- 18. Strengths of this study 1) Access to a large national cohort (TCS) Represents well the Thai population for geographic location, age, and socioeconomic status for both sexes 2) Epidemiologic results remained statistically significant When adjusted for a variety of potential explanatory variables 3) Self-reported heat stress was unlikely to be biased Questionnaires included a substantial number of questions on different exposures and health outcomes Respondents would not be aware of any connection to health outcomes & would not benefit by over or under reporting 18
Editor's Notes
- I’m interested to study on the potential health impacts from heat stress in Thailand because Thailand is a middle income tropical country with around 65 million population . As its rapid urbanization, now 40% of its population live in urban area and predicted by 2030 will be more than 60%. The case of Thailand located in a tropical zone where it is high air temperature (28-30 C) and high humidity (80-90%) Recently, Climate change in Thailand, it is given a lot of attention. According to the study in Thailand, Mean temperature has increased by about 0.74 degrees Celsius over the last 60 years , and it is expected that extreme temperature events will become more prevalent and hotter in the future. The research team from “the southeast Asia START regional centre or SEA START RC) using the regional climate model (from Hadley Center for Climate Change, The Met Office, UK) to predict the annual average of daily Maximum temperature in the future until 2090. And present that temperature will increase in many part of Thailand. So the key point is that, Thailand already have warming temperature and it is expected that temperature extremes events will become more prevalent . Therefore, The effects of daily heat stress exposure can have a major influence on human daily activities but there is limited information regarding the impact on overall health and wellbeing. ------------------------------
- 1. So, this study aims to examine the heat stress effects on daily activities (sleeping, work, daily travel, housework, exercise). 2. And The health and wellbeing impacts from heat stress in our study are categorized as physical health impacts (energy levels), mental health impacts (emotions), and wellbeing (life satisfaction). 3. However. We also concern for the other related factors of age, sex, marital and work status, education, income, urban-rural residence, frequency of exercise and housework, hours of sleep, BMI, smoking , and alcohol consumption)
- The data used in this study were derived from A large national Thai Cohort Study (TCS) of distance-learning open-university adult students aged 15-87 years in 2009 researching the health-risk transition in the Thai population (Sleigh et al, 2008) which the study population are around 60 thousand person (N=60,569) . This study is a cross-sectional study using multinomial logistic regression analysis and adjusting for a wide array of potential confounders.
- Results In this study, heat interference means heat stress causing an uncomfortable feeling when doing these daily activities. The Heat stress question in the TCS questionnaire is: “How often did the hot period this year interfere with the following activities?” 1) sleeping; 2) housework; 3) daily travel; 4) work; and 5) exercise. which respondents answered on a 5 point scale - “not applicable (N/A) – use air conditioning”. “never” “1-3 times/month” classified as “Sometime” and “Often” which mean “everyday” or “1-6 times/wk” Heat interference ‘often’ was reported (in order of frequency) by daily travel, work, housework, sleeping, and exercise. So Daily travel and work were sources of heat stress more often than other activities, probably because they involve time spent in traffic or outdoors during hot periods.
- To measure the health impacts we used questions from the standard Medical Outcomes Short Form Instrument (SF8) as follows 1: Energy levels: “During the past four weeks, how much energy did you have?” Responses were ‘very much’, ‘quite a lot’, ‘some’, and ‘a little’, or ‘none’ 2) Emotions: “During the past four weeks, how much have you been bothered by emotional problems (such as feeling anxious, depressed, or irritable)?” Responses were ‘not at all’, ‘slightly’, ‘moderately’, and ‘quite a lot or ‘extremely’. 3) To measure Wellbeing we used a standardised question: “Thinking about your own life and personal circumstances, how satisfied are you with your life as a whole?” Scores range from 0 (‘completely dissatisfied’) to 10 (‘completely satisfied’). For results: Health and wellbeing frequency outcomes, - around 15% reported having very much energy close to 11% reported no emotional problems And 37·6% reported being very satisfied with their life
- For the association between heat interference with daily activities and health and wellbeing. 1) We found Negative health and wellbeing outcomes associated with increasing frequency of heat stress interfering with daily activities. For those who report higher levels of heat stress interference with daily activities tend to be the ones who have low energy level (between 1·5 and 4.8).
- For those who report higher levels of heat stress interference tend to be the ones who have worse emotional problems (between 1·5 and 4.8).
- And For those who report higher levels of heat stress tend to be the ones who have low life satisfaction (between 1·1 and 2·5).
- 1) We found Negative health and wellbeing outcomes associated with increasing frequency of heat stress interfering with daily activities. For those who report higher levels of heat stress interference with daily activities tend to also be the ones who have adverse health and wellbeing outcomes of emotional problems and in general worse than energy level and life satisfaction 2) Findings show strong and highly consistent trends of adverse health outcomes associated with increasing frequency of heat stress interfered while sleeping, followed by heat stress interfere with daily travel, work, housework and exercise.
- For limitation of this study, We cannot prove that the worse health outcomes occurred at the same time as the heat stress However, The heat-related health outcome models are supported by a dose response whereby more heat stress associated with increased odds of worse health outcomes. 2. The main disadvantage of this study is that it could not directly establish that all those health outcomes arose as a result of heat stress. There are some difficulties in interpreting causality between heat stress and health outcomes given that we cannot be sure that heat stress preceded adverse outcomes 3. Another problem is the unknown source or nature of the heat stress was not reported in the TCS data. Indeed we were not able to make direct measurement of environments or health outcomes and must classify this study as preliminary in nature. Further studies are needed for more detailed direct observations to validate our findings and explore the underlying mechanisms.
- Conclusions: In tropical Thailand, there already are substantial heat stress impacts on health and wellbeing. Increasing temperatures from climate change as well as the growing urban population could significantly worsen the situation. There is a need to improve public health surveillance and public awareness regarding the risks of heat stress in daily life.
- What is heat stress? The definition by American Conference of Industrial Hygienists (ACGIH ) "Heat stress" is the net (overall) heat burden on the body from the combination of *the body heat generated from physical activities, *environmental sources (air temperature, humidity, air movement, radiation from the sun or hot surfaces) and clothing requirements. - Due to the human body is capable of maintaining its core temperature at around 37°C by keep balance between heat gain and heat loss of the body. - So, the natural methods used by humans include convection, conduction, radiation, and evaporation. Only evaporation will lower body temperature in a hot environment. *Evaporation leads to loss of body water and electrolytes by sweating. If there is high humidity, will reduce evaporation and cause less-effective cooling mechanism Therefore, the combination of hot weather and high humidity together with body’s physical exertion and dehydration can overwhelm the body's coping mechanisms leading to cause potentially heat-related illness which could increase adverse health outcomes or possibly fatal conditions.
- This figure give you and example of how heat stress interfered with daily travel in Thailand. The photo obtained from the Bangkok Post Newspaper shows Motorcyclists were using any shade they could find to get through one of the hottest days in summer this year.
- Here is a summary how I build my research questions : Why heat stress is interesting: Because public concern and the current growing worldwide interest in climate change but only Few studies have addressed the health consequences in tropical low and middle income settings such as Thailand. Heat stress is already a problem in tropical countries where both air temperature and humidity is high And rising temperature and rising frequency of hot days from global warming may influence the future pattern of deaths and hospitalization during time of extreme heat in Thailand 2. What we already known from other people work: Increasing temperature in Thailand already occurring The effects of daily heat stress exposure can have a major influence on human daily activities but there is limited information regarding the impact on overall health and wellbeing. 3. What we do not know: this become research question of my study “If temperature increases over time, are there any impacts of heat stress on overall health & wellbeing of Thai population?” 4. Therefore, the Aim of study is to examine the association between self-reported heat stress interference with daily activities and three graded holistic health and wellbeing outcomes among Thai Adults
- The main advantage of my first 4 papers are Access to TCS data with a large national cohort of Thai workers and Thai adults It represents working-age Thais reasonably well for geographic location, age, and socioeconomic status for both sexes The cohort shows a wide range of values for the variables of interest which allowed us to investigate the relationship between heat stress at work and health outcomes 2) These epidemiological results remain substantial and statistically significant when extensively adjusted for a wide array of potential explanatory variables 3) Another strength of these studies is that self-reports of heat stress were unlikely to be biased as the questionnaires included a substantial number of questions on different exposures and health outcomes, we note that questions on heat stress and health outcomes were in different parts of the questionnaire. and respondents would not be aware of any connection to health outcomes.