Association between dairy products and dyslipidemia among the PERSIAN Guilan cohort study population

Dyslipidemia is a major risk factor for cardiovascular diseases, and the role of dairy intake in modulating lipid profiles remains debated. This study aimed to investigate the association between dairy product consumption and dyslipidemia prevalence among adults in the Prospective Epidemiological Research Studies (PERSIAN) Guilan Cohort study (PGCS) population. In this cross-sectional analysis, 10,520 adults aged 35–70 years were included. Demographic and lifestyle factors were recorded, and fasting blood samples were analyzed for total cholesterol, triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Dyslipidemia was defined as cholesterol ≥200 mg/dL, TG ≥150 mg/dL, LDL-C ≥100 mg/dL, or HDL-C ≤40 mg/dL. Dairy intake was categorized into tertiles. Dietary data were assessed using a validated and reliable Persian Food Frequency Questionnaire (FFQ). Overall, 76.4% of participants had dyslipidemia, with 40.3% having hypercholesterolemia, 43.1% hypertriglyceridemia, 29.0% high LDL-C, and 41.5% low HDL-C. Dyslipidemia prevalence showed a non-significant increasing trend with higher dairy intake (P=0.056). No significant trends were found for hypercholesterolemia, hypertriglyceridemia, or high LDL-C. A significant inverse trend was observed between dairy intake and low HDL-C in men (P=0.026); however, this association lost significance after multivariable adjustment (aOR=0.87; 95%CI: 0.73–1.02; P=0.093). This study revealed prevalent dyslipidemia across lipid profiles. Dairy intake showed a non-significant association with overall dyslipidemia and no associations with specific lipid abnormalities. A transient protective trend against low HDL-C in men disappeared post-adjustment, supporting no conclusive link between dairy consumption and dyslipidemia risk.