Effect of Age, Gender, Food Intake, Obesity, and Smoking on Serum Levels of Prolactin in Healthy Adults

Abstract

Objective: The objective of this study was to investigate the effect of age, gender, body mass index (BMI), food intake, and smoking on serum prolactin (PRL) levels among healthy adults. Methods: In total, 100 healthy adults (46 males and 54 females) aged ≥18 years were recruited. Serum PRL levels were measured after a 9 h overnight fast, 1 h postprandially (early), and 3 h postprandially (late). Results: Mean PRL levels were significantly higher in females than males in the fasting, early, and late postprandial states. PRL levels were suppressed significantly after food intake in both genders. Mean PRL levels were significantly higher in younger individuals (<30 years) in the fasting and the early postprandial states compared to older individuals (≥30 years) and suppressed significantly after food intake in younger individuals only. Mean PRL levels were not significantly different between individuals with a normal BMI (<25 kg/m2) compared to those overweight and with obesity (BMI ≥ 25 kg/m2); however, PRL levels were significantly suppressed after food intake only in subjects with a normal BMI. Mean PRL levels did not differ significantly according to smoking status. PRL levels were suppressed significantly after food intake in nonsmokers only. Conclusion: Our data suggest that age, gender, and food intake should be considered when the serum PRL level is measured in clinical practice.