Many illnesses are closely related to seasonal changes. However, the relationship between seasonal changes and fatty liver has not been reported. Therefore, we investigated the relationship between seasonal changes and fatty liver. This study selected three months with lower temperatures between December 2006 and November 2007 (December 2006; January 2007; and February 2007) as the winter season; three of months with higher temperatures (July 2007; August 2007; and September 2007) were designated as the summer season. The individuals undergoing health examinations in a medical centre in southern Taiwan were enrolled as subjects for this research. The patient demographics, smoking and drinking habits, medical history, laboratory findings, and abdominal ultrasound results were collected and analyzed. After excluding those with missing data, 2,026 individuals were eligible for this study. The study cohort included 1197 males (59.1%) and 829 females (40.9%), with a mean age of 50.0±12.6 years. The prevalence of fatty liver in the subjects was 51.8% (n=1,049), with a prevalence of 53.7% in the summer and 48.5% in the winter. Based on univariant analysis, the following were risk factors for fatty liver: season, age, gender, drinking habits, a history of diabetes, a history of hypertension, a history of cardiac disease, an abnormal blood pressure, an abnormal waist circumference, overweight, obesity, hepatitis B carrier, higher fasting plasma glucose levels, higher lipids levels, and abnormal liver function. Using multivariate logistic regression analysis, and after controlling for the multiple risk factors of fatty liver, seasonal changes were still an independent risk factor for fatty liver (p<0.01), and the odds ratio was 1.5. Thus, fatty liver has a higher prevalence in the summer compared to the winter. We therefore suggest that studies focusing on the components of fatty liver should take season into account as possible confounding effects.
Many illnesses are closely related to seasonal changes. However, the relationship between seasonal changes and fatty liver has not been reported. Therefore, we investigated the relationship between seasonal changes and fatty liver. This study selected three months with lower temperatures between December 2006 and November 2007 (December 2006; January 2007; and February 2007) as the winter season; three of months with higher temperatures (July 2007; August 2007; and September 2007) were designated as the summer season. The individuals undergoing health examinations in a medical centre in southern Taiwan were enrolled as subjects for this research. The patient demographics, smoking and drinking habits, medical history, laboratory findings, and abdominal ultrasound results were collected and analyzed. After excluding those with missing data, 2,026 individuals were eligible for this study. The study cohort included 1197 males (59.1%) and 829 females (40.9%), with a mean age of 50.0±12.6 years. The prevalence of fatty liver in the subjects was 51.8% (n=1,049), with a prevalence of 53.7% in the summer and 48.5% in the winter. Based on univariant analysis, the following were risk factors for fatty liver: season, age, gender, drinking habits, a history of diabetes, a history of hypertension, a history of cardiac disease, an abnormal blood pressure, an abnormal waist circumference, overweight, obesity, hepatitis B carrier, higher fasting plasma glucose levels, higher lipids levels, and abnormal liver function. Using multivariate logistic regression analysis, and after controlling for the multiple risk factors of fatty liver, seasonal changes were still an independent risk factor for fatty liver (p<0.01), and the odds ratio was 1.5. Thus, fatty liver has a higher prevalence in the summer compared to the winter. We therefore suggest that studies focusing on the components of fatty liver should take season into account as possible confounding effects.