Health Impact of Climate Patterns on Hospital Admissions due to Cardiovascular Admissions

BACKGROUND:  Although effects of temperature on mortality and some morbidity were examined in prior studies, few if any studies have looked at how weather patterns (large scale tropospheric motion systems) may affect morbidity. This study intended to assess if weather patterns are associated with cardiovascular admissions among persons living in New York State.

METHODS:  Time stratified case-crossover analysis (with up to 6 days lag) was used to assess the association between daily air masses using spatial synoptic classification (SSC) and cardiovascular hospitalizations using a hospitalized discharge database.  The SSC system classified each day into one of 7 different air mass types: dry polar, dry moderate, dry tropical, moist polar, moist moderate, moist tropical or transitional type from 1991 to 2006.  Cardiovascular diseases were defined with ICD-9; 390 – 438.  The analysis was estimated using conditional logistic regression while adjusting for daily ozone and pm2.5.

RESULTS:  Moist tropical air masses during winter were associated with a 3~5% increase (0 – 3 day lag) in admissions. Moist polar during summer showed a significant 1.9~2.1% increase (1 – 3 day lag) in admissions.  Dry polar showed a 0.9~2.5% increase (3 – 6 day lag) in admissions for most seasons except spring.

CONCLUSIONS:  This study identified that unusual seasonal weather patterns such as moist tropical air masses during winter or moist polar air masses during summer had immediate impacts on cardiovascular admissions. But, dry polar air masses showed a delayed effect in most seasons.