1Department of Emergency and Trauma Care, Hainan Medical University, 570102 Haikou, China
2Department of Medicine, Lincoln University College, Wisma Lincoln, 12-18, Jalan SS 6/12, 47301 Petaling Jaya, Selangor, Malaysia
3Department of Pediatrics，Hainan Medical University, 570102 Haikou, China
*Corresponding Author’s Email: farraaidah@lincoln.edu.my
Introduction: The study examines the impact of temperature differences within the same season on blood biochemical levels in cerebral infarction patients in Northeast China and Hainan. To study the effect of temperature differencesin the same season on blood biochemical levels in patients with cerebral infarction in Northeast China and Hainan. Methods: A total of 393 patients with cerebral infarction in a certain area of Northeast China and 343 patients with cerebral infarction in a certain area of Hainan were selected from November 2021 to March 2022, and then the general medical history data and blood biochemical test results of patients with cerebral infarction were collected. A binary logistic regression analysis was performed on the data. Results: In the same quarter, there was a significant correlation between cerebral infarction in patients in Northeast China and Hainan (OR = 0.034, p = 0.000). Gender, smoking, drinking, hypertension, diabetes, coronary heart disease, and triglycerides are high risk factors for cerebral infarction. Conclusion: The incidence of cerebral infarction in patients in Northeast China and Hainan was significantly associated within the same quarter.
Keywords: Blood Biochemical Levels; Cerebral Infarction; Season
Ischemic stroke (cerebral infarction) is a vascular disease characterized by focal neuronal loss and necrosis of brain tissue (Chen et al., 2023). The prevalence of cerebral infarction is increasing annually, and the age of onset is becoming younger. Additionally, the prevalence of risk factors is becoming more apparent, leading to a rising burden of cerebral infarction in China (Zhang et al., 2021; Wang et al., 2022). Studies show that the incidence of cerebral infarction peaks in winter and reaches its lowest point in summer, with meteorological factors being significant risk factors for cerebral infarction. The distribution of cerebral infarction in China exhibits clear geographical differences, with higher rates in the north, lower rates in the south, and a notable prevalence in the central region (Tian et al., 2023). The prevalence of cerebral infarction is higher in the Northeast region, with significantly greater incidence of risk classification and lethality compared to other regions. However, there is a lack of epidemiological data related to the investigation of the regional prevalence of cerebral infarction and its risk factors (Dandan et al., 2021). The aim of this study was to investigate the correlation between temperature changes within the same season and the risk of cerebral infarction in the Northeast and Hainan regions.
From November 2021 to March 2022, 508 people (227 males and 281 females) were selected from a region in Northeast China. Among them, 342 were patients with cerebral infarction (180 males and 162 females). In a region in Hainan, 504 people (275 males and 229 females) were selected, with 393 of them being patients with cerebral infarction (185 males and 208 females).
Meet the diagnostic criteria for ischemic stroke according to the Chinese Guidelines for Diagnosis and Treatment of Acute Ischemic Stroke (2018) (Tian et al., 2023).
Confirmed by clinical examination, CT scan or (and) MRI.
Patients with cardiac, hepatic, renal or pulmonary dysfunction or serious infection.
Those with recent history of craniocerebral trauma as well as surgery.
Transient ischemic attack. The study was approved by the hospital's Ethics Committee, and all subjects signed an informed consent form before participating in the study.
Basic clinical information, including gender, age, systolic blood pressure, diastolic blood pressure, history of alcohol consumption, history of smoking, history of hypertension, history of hyperlipidemia, history of diabetes mellitus, and other risk factors for cerebral infarction, was collected from all study subjects during the same quarter.
Clinical dataincluding creatinine (Crea), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), cystatin C (Cys C), urea nitrogen (BUN) and other biochemical test results were collected from all the study participants in the same quarter, and the differences of the above indexes were compared between the Northeast China and Hainan region.
SPSS 20.0 software was used for data analysis. The count data were expressed as percentages with x2 test; the measurement data conforming to normal distribution and chi-square were expressed as mean±standard deviation (x±s) with t-test; the non-normally distributed measurement data were expressed as M (Q1, Q3) with non-parametric test, and analysed by binary logistic regression, and the differenceof p＜0.05 was considered statistically significant.
Ethical approval for the study was obtained from the Hainan Medical College, China with reference number HYLL-2024-021 on 15th January, 2024.
In the same quarter in Hainan and Northeast China, gender, smoking, alcohol consumption, hypertension, diabetes mellitus, coronary heart disease, systolic blood pressure, diastolic blood pressure, Crea, TG, TC, HDL, LDL, Cys C, and BUN were statistically significant (p<0.05), and age was not statistically significant (p>0.05) (Table 1).
Table 1: Analyses of Population-Related Data in Hainan and Northeast Regions
Sports Event | Hainan 504 | Northeast 508 | z/x2 | p |
Distinguishing between the Sexes | 275/229 | 227/280 | 10.684 | 0.005 |
Age | 56 (64, 72) | 64 (57, 72.75) | -0.496 | 0.620 |
Non-Smoking/Smoking | 418/86 | 304/204 | 65.999 | 0.000 |
Non-Drinking/Drinking | 381/123 | 316/192 | 21.160 | 0.000 |
History of Hypertension | 328/176 | 277/407 | 1.716 | 0.001 |
History of Diabetes | 413/91 | 476/32 | 32.750 | 0.000 |
History of Coronary Heart Disea se | 473/31 | 450/58 | 8.748 | 0.003 |
Systolic Blood Pressure | 132 (119, 148) | 140 (130, 149.75) | -3.363 | 0.001 |
Diastolic Blood Pressure | 79 (73, 91) | 80 (70, 81) | -4.109 | 0.000 |
Creatinine | 69.8 (56.5, 83.4) | 60.4(48.52,72.8) | -7.287 | 0.000 |
Triglycerides (mmol/L) | 0.98 (0.70,1.38) | 1.35 (0.94,1.84) | -7.992 | 0.000 |
Total Cholesterol (mmol/L) | 4.44 (3.74, 5.05) | 4.03 (3.25,4.59) | -7.473 | 0.000 |
High-Density Lipoprotein (mmol/L) | 1.40 (1.10, 1.60) | 1.24 (1.06,1.38) | -7.417 | 0.000 |
Low-Density Lipoprotein (mmol/L) | 2.91 (2.25, 3.63) | 2.26 (1.64,2.81) | -12.155 | 0.000 |
Cystatin C | 1.02 (0.87,1.18) | 0.84(0.69,1.00) | -10.376 | 0.000 |
Urea Nitrogen | 4.1 (3.1, 5.2) | 5.38 (4.2, 6.74) | -10.647 | 0.000 |
In the population of cerebral infarction in Hainan and Northeast China in the same quarter, alcohol consumption, diabetes, coronary heart disease systolic blood pressure, diastolic blood pressure, Crea, TG, TC, HDL, LDL, Cys C, and BUN were statistically significant (p<0.05), and gender, age, and hypertension were not statistically significant (p>0.05) (Table 2).
Table 2: Population Analyses of Cerebral Infarction in Hainan Region and Northeast Region
Sports Event | Northeast Cerebral Infarction (n=393) | Hainan Cerebral Infarction (n=342) | t/x2 | p |
Distinguishing Between the Sexes | 185/208 | 180/162 | 2.260 | 0.133 |
Age | 65 (57, 73) | 65 (57,72) | -0.448 | 0.654 |
Non-Smoking/Smoking | 197/196 | 284/58 | 87.595 | 0.000 |
Non-Drinking/Drinking | 205/188 | 253/89 | 37.053 | 0.000 |
History of Hypertension | 184/209 | 172/170 | 0.883 | 0.347 |
History of Diabetes | 366/27 | 251/91 | 52.862 | 0.000 |
History of Coronary Heart Disease | 339/54 | 311/31 | 3.910 | 0.048 |
Systolic Blood Pressure | 140 (130, 150) | 134 (121, 149) | -2.391 | 0.017 |
Dia stolic Blood Pressure | 80 (70, 90) | 80 (73, 91) | -4.235 | 0.000 |
Creatinine | 61.4 (48.6, 72.85) | 69.8 (55.8, 84.47) | -5.619 | 0.000 |
Triglycerides (mmol/L) | 1.49 (1.09, 2.00) | 1.09(0.79,1.69) | -6.078 | 0.000 |
Total Cholesterol (mmol/L) | 3.76 (3.04, 4.52) | 4.57 (3.82, 5.44) | -9.782 | 0.000 |
High-Density Lipoprotein (mmol/L) | 1.26 (1.08, 1.38) | 1.4 (1.1, 1.6) | -5.867 | 0.000 |
Low-Density Lipoprotein (mmol/L) | 2.1 (1.45, 2.71) | 3.16 (2.52, 3.94) | -13.826 | 0.000 |
Cystatin C | 0.82 (0.66, 0.99) | 1.05 (0.89, 1.23) | -9.929 | 0.000 |
Urea Nitrogen | 5.54 (4.21, 6.92) | 4.1 (3.0, 5.4) | -9.268 | 0.000 |
Acute cerebral infarction was used as the dependent variable, while the region was set as the subvariable, and gender, smoking, alcohol consumption, hypertension, diabetes, coronary heart disease, TG, and BUN were included in the regression model analysis using stepwise method as the independent variables. The results showed a significant association between the occurrence of cerebral infarction in patients from the Northeast and Hainan regions within the same quarter (OR=0.034; p=0.000). Gender, smoking, alcohol consumption, hypertension, diabetes mellitus, coronary heart disease, and TG were all high-risk factors for developing cerebral infarction (Table 3).
Table 3: Logistic Regression Analysis
Variables in the Equation | |||||||||
Characteristics | B | Standard Error | Vardø | Degrees of Freedom | Significance | EXP (B) | 95% Confidence Interval for EXP(B) | ||
Lower Limit | Limit | ||||||||
Step 8h | Distinguishing between the Sexes | 0.444 | 0.190 | 5.457 | 1 | 0.019 | 1.559 | 1.074 | 2.263 |
Smoking | 0.668 | 0.249 | 7.189 | 1 | 0.007 | 1.950 | 1.197 | 3.176 | |
Drink (Alcohol) | 1.401 | 0.245 | 32.763 | 1 | 0.000 | 4.058 | 2.512 | 6.556 | |
Hypertensive | 1.982 | 0.235 | 70.916 | 1 | 0.000 | 7.260 | 4.577 | 11.517 | |
Diabetes | 2.219 | 0.501 | 19.610 | 1 | 0.000 | 9.201 | 3.446 | 24.573 | |
Coronary Heart Disea se | 1.995 | 0.560 | 12.701 | 1 | 0.000 | 7.352 | 2.454 | 22.023 | |
Triglyceride | 1.975 | 0.213 | 85.751 | 1 | 0.000 | 7.209 | 4.746 | 10.951 | |
Urea Nitrogen | .032 | 0.024 | 1.775 | 1 | 0.183 | 1.032 | 0.985 | 1.082 | |
Constant | -3.379 | 0.424 | 63.583 | 1 | 0.000 | 0.034 | |||
The incidence of acute cerebral infarction (ACI) is negatively correlated with mean daily temperature, especially in cold temperatures, which are more likely to cause ACI. Low temperature is one of the risk factors for the development of acute cerebral infarction, while high temperature may play a protective role (Yanan et al., 2018; Okubo et al., 2024). Patients with ischemic cerebral infarction are admitted to hospital more frequently in winter than in other seasons (Lei, 2024; Elbqry et al., 2019). Due to the decrease in plasma volume and increase in plasma viscosity in winter, platelet, cholesterol and fibrinogen concentrations increase, while the increase in protein-free C leads to an increase in atherothrombotic risk factors (Chu et al., 2018). Studies have shown that the risk of cerebral infarction in patients rises by 3% for each additional cold day in the week prior to the onset of infarction. For each additional cold day in the summer, the patient's probability of having a cerebral infarction also increased by 8%. This association was positively related to cold weather and ischaemic stroke, but not to haemorrhagic stroke (Vaičiulis et al., 2023). The study found that nighttime blood pressure was lower than morning in all months, with the lowest blood pressure in August. Outdoor temperatures were also highest in August (Izumi & Suzuki, 2021). In cold climates, both normotensive and hypertensive individuals showed varying degrees of elevated systolic blood pressure, with hypertensive individuals showing more pronounced blood pressure fluctuations. Blood pressure fluctuations are negatively correlated with temperature changes (Weiwei et al., 2011). Studies have shown that the association between cold and stroke is stronger in the male population (Luo et al., 2018).
The incidence and mortality rates of stroke were highest in the north-eastern region (365 and 159 per 100,000 person-years), followed by the central region (326 and 154 per 100,000 person-years); the prevalence of stroke was highest in the central region (15.5 per 100,000 person-years), followed by the north-eastern region (14.5 per 100,000 person-years), and lower in the southern region (625 per 100,000 person-years). The geographical difference in the incidence of cerebral infarction is consistent with its geographical distribution, which is "high in the north, low in the south, and prominent in the centre" (de Havenon et al., 2021, Purnama et al., 2024). A new study shows that the rate of hypertension is the highest in North China, reaching 39.09%, and the lowest in South China, 29.41%; the rate of dyslipidaemia is the highest in Northwest China, 38.81%, and the lowest in East China, 31.94%; and the rate of diabetes mellitus is close to the same rate in different regions and there is no significant difference (Wang et al., 2022). It can be seen that the risk factors of cerebral infarction also have regional differences.
The incidence of acute cerebral infarction (ACI) is significantly influenced by temperature, with colder weather increasing the risk, especially in winter when blood viscosity and related risk factors are higher. Geographically, the incidence and mortality rates of stroke vary, being highest in the north-eastern and central regions of China. These regional differences correlate with varying rates of hypertension, dyslipidaemia, and other risk factors, underscoring the importance of regional and seasonal considerations in managing and preventing ACI (Cho, 2024).
This study has some limitations. Firstly, this study is a retrospective study, and the selected clinical information comes from hospital case data, which may have some information bias and selection bias. Second, only a few districts were selected for analysis in this study, which have increased the selection of districts. In conclusion, the association between region and the occurrence of cerebral infarction in patients was significant in the same quarter.
This study highlights the significant impact of seasonal temperature differences on blood biochemical levels and the incidence of cerebral infarction in Northeast China and Hainan. Cold temperatures are associated with increased risk factors such as elevated triglycerides, cholesterol, and blood pressure, leading to a higher incidence of cerebral infarction. The findings reveal substantial regional differences, with the colder Northeast region showing higher stroke rates compared to the warmer Hainan region. These results underscore the need for region-specific preventive measures that account for both seasonal and geographic variations. Future research should further explore these relationships to develop effective, targeted strategies for stroke prevention.
The authors declare that they have no competing interests.
Authors are thankful to the faculty of medical science and management of Lincoln University College, Malaysia for providing all the necessary support and facilities to complete the present study.
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