Climatic influences on cardiovascular diseases

Table 4 Main studies on the relations between weather and acute coronary syndromes

Ref.	Population and setting	Year	Main results
Mirić et al[78]	Coastal part of middle Dalmatia (Croatia)	1981-1987	Significant association of acute myocardial infarction incidence with increased air temperature four days before, and on the day of the incident (P < 0.05)
Danet et al[73]	Morbidity registry (Lille-WHO MONICA Project) monitoring 257000 men Aged 25-64 years.	1985-1994	The events rate decreased linearly with increasing atmospheric temperature: a 10°C decrease was associated with a 13% increase in event rates
Wichmann et al[49]	AMI hospitalisationsin Gothenburg, Sweden	1985-2010	A linear exposure-response corresponding to a 3% and 7% decrease in AMI hospitalisations was observed for an inter-quartile range increase in the 2-d cumulative average of temperature during the entire year and the warm period, respectively
Abrignani et al[74]	Hospital admissions for acute myocardial infarction in Trapani, Italy	1987-1998	Significant association as regards the incidence relative ratio between daily number of myocardial infarction hospital admission and minimal daily temperature
Abrignani et al[82]	Hospital admissions for angina pectoris in Trapani, Italy	1987-1998	Significant association between daily number of angina hospital admission and temperature. Significant incidence relative ratios (95%CI) were, in males, 0.988 (0.980–0.996) (P < 0.004) for minimal temperature. The corresponding values in females were 0.973 (0.951–0.995) (P < 0.017) for maximal temperature and 1.024 (1.001–1.048) (P < 0.037) for minimal temperature
Marchant et al[37]	633 consecutive patients with myocardial infarction admitted to a coronary care unit in London, United Kingdom	1988-1991	Excess of infarctions on colder days in both winter and summer
Bayentin et al[77]	Quebec, Canada	1989-2006	Cold temperatures during winter and hot episodes during summer are associated with an increase of up to 12% in the daily hospital admission rate for CHD. In most regions, exposure to a continuous period of cold or hot temperature was more harmful than just one isolated day of extreme weather
Wolf et al[64]	Myocardial infarctions and coronary deaths in the Monitoring Trends and Determinants on Cardiovascular Diseases/Cooperative Health Research in Augsburg (MONICA/KORA) Registry, Germany	1995-2004	A 10°C decrease in 5-d average temperature was associated with a relative risk of 1.10 (95%CI: 1.04-1.15). Effect of temperature on the occurrence of nonfatal events showed a delayed pattern, whereas the association with fatal forms was more immediate
Madrigano et al[70]	Patients with a possible discharge diagnosis of AMI in 11 acute care general hospitals serving residents of the Worcester metropolitan area (Worcester Heart Attack Study), United Kingdom	1995, 1997, 1999, 2001, 2003	A decrease in an interquartile range in apparent temperature was associated with an increased risk of acute myocardial infarction on the same day [HR = 1.15 (95%CI: 1.01–1.31)]. Extreme cold during the 2 d prior was associated with an increased risk of acute myocardial infarction [1.36 (1.07–1.74)]. Exposure to heat increased the risk of dying after an AMI
Mohammad et al[72]	All myocardial infarctions reported to the Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies (SWEDEHEART)	1998-2013	The most pronounced association was observed for air temperature, where a 1-SD increase (7.4°C) was associated with a 2.8% reduction in risk of myocardial infarction (incidence ratio, 0.972; 95%CI: 0.967-0.977; P < 0.001). Results were consistent for non–ST-elevation as well as ST-elevation myocardial infarction and across a large range of subgroups and health care regions
Messner et al[76]	Subarctic area of Northern Sweden	2001	A 1°C temperature rise was associated with an 1.5% increase in the number of nonfatal acute myocardial infarctions
Chang et al[69]	Myocardial infarctions among women aged 15–49 from 17 different countries in Africa, Asia, Europe, Latin America, and the Caribbean	2003	Overall, a 5°C drop in temperature was associated with a 12% increase in admissions for heart attack (incidence rate ratio 0.88 (95%CI: 0.8-0.97)
Misailidou et al[65]	Five rural Greek regions (Karditsa, Lamia, Chalkida, Kalamata and Zakinthos)	2003-2004	For an 18°C decrease in temperature there was a 1.6% (95%CI: 0.9%–2.2%) increase in admissions for CHD
Bhaskaran et al[63]	84010 hospital admissions for myocardial infarction in the Myocardial Ischaemia National Audit Project (15 conurbations in England and Wales, United Kingdom)	2003-2006	Broadly linear relation between temperature and myocardial infarction, without a threshold: each 1°C reduction in daily mean temperature was associated with a 2.0% (95%CI: 1.1%-2.9%) cumulative increase in risk of myocardial infarction over the current and following 28 d, the strongest effects being estimated at intermediate lags of 2-7 and 8-14 d. Heat had no detrimental effect
Nastos et al[80]	Crete, Greece	2004-2007	The impact of weather variability on the ACS incidence is not statistically significant
Ravljen et al[68]	ACS treated with coronary emergency catheter interventions in Slovenia	2008-2011	Daily average temperature, atmospheric pressure and relative humidity all have relevant and significant influences on ACS incidences for the entire population. However, the ACS incidence for population over 65 is only affected by daily average temperature
Hori et al[71]	Japan	2010	Every 1°C decrease in mean temperature was associated with an increase in the daily number of emergency admissions for ACS by 7.83% (95%CI: 2.06-13.25)
García-Lledó et al[66]	Madrid, Spain	2013-2017	The minimum incidence rate of myocardial infarction was observed at the maximum temperature of 18°C. Warmer temperatures were not associated with a higher incidence (RR, 1.03; 95%CI: 0.76-1.41), whereas colder temperatures were significantly associated with an increased risk (IRR, 1.25; 95%CI: 1.02-1.54)
Lin et al[67]	Hospitalizations for CHD in New York State, United States	2015	Extremely low universal apparent temperature in winter was associated with increased risk of AMI, especially during lag4-lag6
Sharif Nia et al[75]	Hospital admission for AMI in Mazandaran Province, Iran	2015-2016	Daily minimum temperature correlated with ACS events [RR = 0.942 (95%CI: 0.927-0.958), P < 0.001]

ACS: Acute coronary syndromes; AMI: Acute myocardial infarction; CHD: Coronary heart disease; CI: Confidence interval; RR: Relative risk; SD: Standard deviation.