The Effect of Season and Temperature Variation on Hospital Admissions for Incident Stroke Events in Maputo, Mozambique

Abstract

Background Identifying locale-specific patterns regarding the variation in stroke incidence throughout the year and with atmospheric temperature may be useful to the organization of stroke care, especially in low-resource settings. Goal We aimed to describe the variation in the incidence of stroke hospitalizations across seasons and with short-term temperature variation, in Maputo, Mozambique. Methods Between August 1, 2005, and July 31, 2006, we identified 651 stroke events in Maputo dwellers, according to the World Health Organization's STEPwise approach. The day of symptom onset was defined as the index date. We computed crude and adjusted (humidity, precipitation and temperature) incidence rate ratios (IRRs) and 95% confidence intervals (CIs) with Poisson regression. Results Stroke incidence did not vary significantly with season (dry versus wet: crude IRR 5 .98, 95% CI: .84-1.15), atmospheric temperature at the index date, or average atmospheric temperature in the preceding 2 weeks. The incidence rates of stroke were approximately 30% higher when in the previous 10 days there was a decline in the minimum temperature greater than or equal to 3°C between any 2 consecutive days (variation in minimum temperature −5.1 to −3.0 versus −2.3 to −.4, adjusted IRR = 1.31, 95% CI: 1.09-1.57). No significant associations were observed according to the variation in maximum temperatures. Conclusions Sudden declines in the minimum temperatures were associated with a higher incidence of stroke hospitalizations in Maputo. This provides important information for prediction of periods of higher hospital affluence because of stroke and to understand the mechanisms underlying the triggering of a stroke event.

The relationship between ischemic stroke and weather conditions in Duzce, Turkey

“…Studies [6,7,14,16] found that there was no relationship between daily cases and changes of weather conditions, and others [10,[17][18][19][20] reported relationships between daily cases and changes of weather conditions.…”

“…A strong relationship was observed between IS and decrease of air temperature. [17] Gomes et al [18] found a relationship between stroke incidence and a decline in minimum temperature ≥3 °C in 2 of consecutive 10 days. In another study Gomes et al [19] found that a decline of minimum temperature >2.4 °C in any 2 consecutive days in a week and stroke incidence are significantly correlated.…”

“…These two studies were performed in Maputo, Mozambique where daily temperature varies between 14 °C and 30 °C throughout the year. [18] The temperature in Maputo may affect the results of these studies. Additionally, cases of stroke, hemorrhagic and ischemic, were included in the studies, but cases of ischemic and hemorrhagic stroke are significantly different in clinical entities and pathophysiology.…”

Circadian Variation in the Incidence of Stroke-Induced Aphasia Types in Ahvaz, South-West of Iran

“…The time and climatic features in the incidence of stroke and aphasia are among these factors, which were vastly studied in some countries (13)(14)(15)(16)(17)(18)(19). According to the statistical information in Italy, the incidence of stroke is lower during the summer and is higher in the fall than in the winter (20).…”

On the Causal Paths Underlying the Relation between Atmospheric Temperature and Acute Stroke

“…We thank Al Mamun et al 1 for their interest in our work 2 and for giving us the opportunity to further discuss the causal relations potentially underlying the triggering of stroke events by atmospheric temperature. In general, we agree with their arguments regarding the interplay between several orders of factors, which we explore below offering a framework for future research.…”