F Raiszadeh | PubMed Health

PubMed2003

Serum paraoxonase 1 activity is decreased in thyroid dysfunction.

Changes in serum lipid and lipoprotein concentrations occur frequently in disorders of thyroid function. LDL-cholesterol (LDL-C) oxidation susceptibility is higher in these patients than in normal population. This study aims at assessing lipids, lipoproteins, apolipoproteins and serum paraoxonase 1 (PON1) activity in patients with thyroid dysfunction. Ninety-nine patients with thyroid dysfunction, (49 hypothyroid and 50 hyperthyroid) were compared with 2 separately age- and sex-matched control groups. A fasting blood sample was obtained and serum total cholesterol, triglycerides, apolipoproteins A-I and B, and PON1 activity were measured. In hyperthyroid patients, significantly lower PON1 activity (45 +/- 23 vs 67 +/- 37 IU/ml, p<0.001), triglycerides (112 +/- 53 vs 166 +/- 130 mg/dl, p<0.05), apolipoprotein A-I (137 +/- 26 vs 154 +/- 21 mg/dl, p<0.001) and apolipoprotein B (75 +/- 18 vs 86 +/- 25 mg/dl, p<0.05) were found. Hypothyroid patients had lower PON1 activity (46 +/- 21 vs 64 +/- 32 IU/ml, p<0.005) compared with controls, and higher total cholesterol (224 +/- 69 vs 185 +/- 41 mg/dl, p<0.001), LDL-C (133 +/- 59 vs 93 +/- 36 mg/dl, p<0.001), and apolipoprotein B (107 +/- 37 vs 84 +/- 23 mg/dl, p<0.001). The results show significant changes of lipid levels in thyroid dysfunction. In addition, a significant reduction in PON1 activity was observed in both hyper- and hypothyroid patients. Increased LDL-C oxidation in thyroid dysfunction observed in other studies, at least to some extent, can be attributed to reduced PON1 activity.

Adult↗

PubMed2002

Determinants of serum HDL-C level in a Tehran urban population: the Tehran Lipid and Glucose Study.

BACKGROUND AND AIM: Decreased serum high-density lipoprotein cholesterol (HDL-C) is one of the most common lipid disorders in patients with coronary artery disease (CAD). Existing evidence suggests that every 1 mg/dL decrease in serum HDL-C increases the risk of CAD by 2-3%. This study was performed in the year 2000 to study HDL-C determinants in a Tehran population. METHODS AND RESULTS: We studied 9514 subjects (3942 men and 5572 women) aged 20-69 years, who participated in the Tehran Lipid and Glucose Study (TLGS), completed a personal history questionnaire (especially concerning physical activity and cigarette smoking), and underwent a clinical examination including anthropometric and blood pressure measurements. Serum total cholesterol, triglyceride and HDL-C levels were measured, and OGTT was used to define diabetic patients according to WHO criteria. The women had a significantly higher mean HDL-C level than the mean (45 +/- 11 vs 38 +/- 9 mg/dL; p < 0.001); low HDL-C levels (< 35 mg/dL) were observed in 31% of the men and 13% of the women (p < 0.001). Obese subjects (BMI > or = 30 kg/m2) had a significantly lower HDL-C level than the normal subjects (42 +/- 11 vs 44 +/- 11 mg/dL: p < 0.001), and those with truncal obesity (WHR > or = 0.95 in men and > or = 0.8 in women) lower HDL-C levels than the normal subjects (37 +/- 9 vs 39 +/- 10 mg/dL in men and 44 +/- 11 vs 42 +/- 11 mg/dL in women; p < 0.001 for both). Smokers had a significantly lower HDL-C level than non-smokers (38 +/- 10 vs 43 +/- 11 mg/dL; p < 0.001) and a low HDL-C level was twice as common (36.4 vs 18.2%). Passive smokers also had lower HDL-C levels (42 +/- 11 vs 43 +/- 11 mg/dL; p < 0.001). Mean serum HDL-C was significantly lower in hypertriglyceridemic than those with normal triglycerides levels (men: 4 +/- 8 vs 40 +/- 9 mg/dL, p < 0.001; women: 40 +/- 10 vs 47 +/- 11 mg/dL, p < 0.01). Mean HDL-C levels were similar in subjects with different degrees of physical activity, as well as between diabetics and non-diabetics and hypertensive and normotensive subjects. Multiple stepwise regression analysis showed that the determinants of serum HDL-C levels were, in order of entering the model: hypertriglyceridemia (OR 3.4, p < 0.001), male sex (OR 3.1, p < 0.001), cigarette smoking (OR 1.7, p < 0.001), obesity (OR 1.4, p < 0.01), age (OR 0.9, p < 0.05), high WHR (OR 1.2, p < 0.05), and passive smoking (OR 1.1, p < 0.05). Physical activity, hypertension, and diabetes mellitus did not enter the predictive model. CONCLUSION: Apart from age and sex which are constitutional, and unmodifiable variables, the determinants of HDL-C level (hypertriglyceridemia, obesity, truncal obesity, cigarette smoking, and passive smoking) can be used in community CAD prevention programmes.

Adult↗