Research and Surveillance Corner

Climate Change Research

The following studies were conducted by researchers at NYSDOH to explore a variety of climate change factors on human health.

Evaluating the Health Impact of a Blackout

This study assessed the health effects of the 2003 Northeastern blackout on mortality and hospital admissions due to respiratory, cardiovascular, and renal diseases in New York City (NYC). State health researchers investigated the effects of the blackout on health using incidence rate ratios to compare the disease on blackout days (August 14 and 15, 2003) with those on normal June-August days and comparably hot days when the maximum temperatures were the same as on the blackout days.

They found that mortality and respiratory hospital admissions in NYC increased during the blackout, but cardiovascular and renal hospitalizations did not. The most striking increases occurred among elderly, female, and chronic bronchitis admissions. Symptoms appeared to be more severe during the blackout than on comparably hot days. Higher income/education groups were also more likely to be hospitalized during the blackout than on comparably hot days as well.

This study suggests that power outages may have important health impacts, even stronger than the effects of heat alone. These findings provide some insights for future emergency planning and public health preparedness.

Link to article Health Impact in New York City During the Northeastern Blackout of 2003
Citation Lin S, Fletcher B, Luo M, Chinery R, Hwang SA. Health impact in New York City during the Northeastern (US) Blackout of 2003. Public Health Reports 2011; 126(3):384-393.

Exploring the Relationship between Extreme Summer Temperatures and Birth Defects

Previous studies have shown that pregnant women experiencing high fevers over long time periods during the important fetal development stages can cause possible birth defects. This study explores the relationship between extreme temperatures and several major birth defects to determine whether pregnant women and their developing infants are potentially vulnerable to effects of climate change.

Results of the study showed that with a single day 5℉ increase in outdoor temperature during the critical period of fetal organ development there was an increase in the risk of developing congenital cataracts, which is a clouding of the lens of the eye that is present at birth. This risk nearly doubled if pregnant women experience a heat wave with prolonged exposure to high temperatures during that critical period. Although this relationship was found to be significant in various measures of heat in this study, there is more research to be done in this area of climate change and health.

Link to article A Population-Based Case-control Study of Extreme Summer Temperature and Birth Defects
Citation Van Zutphen AR, Lin S, Fletcher BA, Hwang SA. A population-based case-control study of extreme summer temperature and birth defects in New York State. Environmental Health Perspectives. Online ahead of print 27 Jun 2012 |

Hot Summer Temperatures and Renal Disease

Renal disorders are diseases that affect the kidneys, making it difficult for the body to maintain a proper fluid balance. Exposure to extreme or prolonged heat can worsen chronic diseases like kidney disorders. State health researchers examined the risk of hospitalization for acute renal failure in New York State during periods of extreme summer time heat. The study also examined how factors like geographic location, age, sex, race, ethnicity, or income affected hospitalizations for renal disease during periods of extreme heat.

This study found that for every 5℉ increase in daily average temperature there was a 9% increase in the risk of hospitalization for acute renal failure on the following day. The study identified a higher risk of hospitalization for acute renal failure among Blacks and Hispanics; people aged 25-44 years; and those in the lowest income range. People living in urban regions were found to be more at risk for hospitalization compared to people living in rural or suburban neighborhoods.

Acute renal failure can be caused by heat stroke, direct kidney damage or dehydration. This indicates the importance of hydration during extreme temperatures, and the need to promote good hydration especially among higher risk populations.

Link to article Association of Summer Temperatures With Hospital Admissions for Renal Diseases in New York State: A Case-Crossover Study
Citation Fletcher B, Lin S, Fitzgerald EF, Hwang SA. Association of Summer Temperatures With Hospital Admissions for Renal Diseases in New York State: A Case-Crossover Study. Am J Epidemiol. May 2012; 175(9):907-916

Summer Time Temperature Variations and Respiratory Health in New York State

While increases in temperature have been shown to have an effect on various health outcomes, variations in daily temperature are also suspected to have an impact. Specifically, not many studies have examined the effect of daily temperature fluctuations on respiratory outcomes.

To address these gaps in research, State health researchers examined if daily or multiday temperature variations during the summer season had an impact on respiratory health in New York State. This impact was measured both at statewide and at regional levels using a 1.8℉ change in temperature to determine the increase in risk of hospital admissions for respiratory diseases.

Researchers observed that differences in the highest and lowest temperatures on a given day affected respiratory admissions in NYS. On days with larger differences between the highest and lowest temperatures, there was an increased risk of hospitalization for respiratory diseases 2-4 days later. Temperature variation over multiple days showed a proportionally higher increase in respiratory admissions when compared to single day variations. This indicates that while extreme heat can impact health, temperature variations can also influence the risk of hospitalization.

Link to article The effects of ambient temperature variation on respiratory hospitalizations in summer, New York State
Citation Shao Lin, Tabassum Z. Insaf, Ming Luo, Syni-An Hwang. The effects of ambient temperature variation on respiratory hospitalizations in summer, New York State. International Journal of Occupational and Environmental Health, Jul-Sep 2012;18(3):188-97.

Examining Climate Trends in New York State

In New York State, different areas may experience differences in the effects of climate change. State health researchers examined 60 years (1948-2008) of data to identify annual and seasonal patterns in temperature and precipitation across time and geographic location in New York State.

The results of the study suggest that the nighttime temperatures have become warmer while the annual number of days below freezing have decreased. Trends toward warmer temperatures have also affected the length of the growing season in NYS. Yearly amounts of precipitation have also increased.

The indicators that have been identified in this study should be further evaluated and assessed for their health impact. Warmer and wetter weather may result in an in increase in mold and allergens, and may also alter the life cycle of the tick. Identifying these patterns in climate is important because these changes can affect public health through asthma, allergies and Lyme disease.

Link to article Climate trends in indices for temperature and precipitation across New York State, 1948-2008
Citation Insaf TZ, Lin S, Sheridan SC. Climate trends in indices for temperature and precipitation across New York State, 1948-2008. Air Quality, Atmosphere, & Health. 2013 March; 6(1): 247-257.

The Costs of Current and Future Climate Change on Respiratory Health in New York State

Current evidence shows a strong relationship between extreme heat days and increases in respiratory diseases. However, few studies have described the economic costs associated with climate change and health. State health researchers studied the impacts of increased respiratory disease hospitalizations resulting from extreme heat in summer in New York State by region and demographic population. They estimated the impact of extreme summer heat based on estimates of the costs and loss of productivity due to respiratory hospitalizations associated with extreme heat days. Estimates were calculated for three possible climate scenarios developed based on combinations of expected population growth, economic development and technological changes.

The estimated costs resulting from respiratory disease hospitalizations attributed to extreme heat varied by region. Current estimates attribute approximately 100 excess hospital admissions and nearly 616 days of hospitalization per year to extreme heat, resulting in an estimated US $644,069 in direct hospitalization costs. Future projections for the years 2080-2099 project a 2- to 6-fold increase in hospital admissions and an estimated US $26-76 million dollars in hospital costs. When combined with other heat-associated diseases and mortality, the potential public health burden associated with global warming could be substantial.

Link to article Excessive heat and respiratory hospitalizations in New York State: estimating current and future public health burdon related to climate change
Citation Lin S, Hsu WH, Van Zutphen AR, Saha S, Luber G, Hwang SA. Excessive heat and respiratory hospitalizations in New York State: estimating current and future public health burden related to climate change. Environ Health Perspect. 2012 Nov;120(11):1571-7. doi: 10.1289/ehp.1104728. Epub 2012 Aug 24