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Seasonal variation in high density lipoprotein cholesterol
M Mänttäri1, K Javela, P Koskinen
1First Department of Medicine, Helsinki University, Finland.
Insights
High-density lipoprotein cholesterol (HDL) levels in middle-aged men show a significant seasonal variation, dropping in winter. This pattern was not directly linked to coronary heart disease incidence.
Area of Science:
- Cardiovascular Health
- Lipid Metabolism
- Seasonal Health Variations
Background:
- Dyslipidemia affects middle-aged men, with high-density lipoprotein cholesterol (HDL) being a key indicator.
- Understanding HDL fluctuations is crucial for cardiovascular risk assessment.
Purpose of the Study:
- To investigate the seasonal variation in HDL cholesterol levels among dyslipidemic men.
- To determine factors influencing HDL seasonality and its relation to coronary heart disease (CHD).
Main Methods:
- Analysis of HDL cholesterol levels over a 5-year period in the placebo group of the Helsinki Heart Study.
- Inclusion of 142 middle-aged men with dyslipidemia (non-HDL-cholesterol >= 5.2 mmol/l).
- Assessment of factors including age, alcohol, diet, physical activity, triglycerides, smoking, and body weight.
Main Results:
- A significant seasonal pattern in HDL was observed, with a 4.5% drop during mid-winter.
- HDL levels were lower in winter (mean 1.192 mmol/l) compared to the rest of the year (mean 1.248 mmol/l).
- Seasonal HDL variation showed an inverse relationship with body weight fluctuations and was not directly reflected in CHD incidence.
Conclusions:
- HDL cholesterol exhibits a distinct seasonal variation in dyslipidemic middle-aged men, peaking in summer and troughing in winter.
- Factors like diet, exercise, and alcohol did not influence HDL seasonality, though smoking had a slight effect.
- The observed seasonal HDL variation did not correlate with changes in coronary heart disease incidence.
Abstract:
We investigated the seasonal variation in high density lipoprotein cholesterol (HDL) in 142 dyslipidemic (non-HDL-cholesterol > or = 5.2 mmol/l) middle-aged men in the placebo group of the Helsinki Heart Study over the 5-year trial period. A seasonal pattern was found in HDL fluctuation, with a 4.5% drop during mid-winter (5-year mean 1.192 +/- 0.265 mmol/l) compared with a stable level (5-year mean 1.248 +/- 0.281 mmol/l) during the rest of the year (P < 0.001). A less pronounced seasonal variation in HDL was observed in 85 subjects receiving gemfibrozil. Although affecting pretrial HDL level in cross-sectional analyses, age, alcohol consumption, dietary adherence, physical activity and serum triglycerides had no influence on the seasonality of HDL variation. Smoking had a slight attenuating effect on the variation pattern. Pretrial HDL was influenced by relative weight, but there was also an inverse relationship between HDL and body weight variations, i.e. the annual drop in HDL coincided with the annual peak in body weight. However, seasonal HDL variation was not directly reflected in the annual variation in CHD incidence.