Doctoral Student Presents on Smoking and Homocysteine Levels

Ogbebor Omoike, student in East Tennessee State University College of Public Health’s doctoral program, presented at the American College of Epidemiology’s Annual Meeting in Pasadena, California in September 2019.  The presentation, “Association between smoking status and homocysteine levels and possible effect modification by cholesterol and estradiol” discusses the amino acid homocysteine and its possible relationship with whether or not a person smokes.

Environmental and dietary exposures alter the levels of homocysteine in the human body; however, little is known about the association of smoking status with homocysteine levels. This study aimed to examine the association of smoking status with homocysteine levels and to determine whether the association is modified by estradiol, a female hormone, or cholesterol, a type of lipid.

Data were obtained from National Health and Nutrition Examination Survey 2003-2004 with analysis done in 2018 on 4,580 adults aged 20 years and older. A current smoker defined as a person who smoked at least 100 cigarettes in his/her lifetime and at least once in the last month; a former smoker is one who had smoked less than 100 cigarettes and had quit smoking at the time of the interview; a “never smoker” is an adult who never smoked cigarettes in their lifetime or less than 100 cigarettes in his/her lifetime.

After adjusting for age, sex, ethnicity, education, and income level, homocysteine levels did differ by smoking status. The addition of estradiol as an effect modifier in adjusted models was associated with a 17% increase in homocysteine levels when compared to models without the effect modifier. Estradiol but not cholesterol did moderate the association between smoking status and homocysteine levels.

The study concluded that homocysteine levels did differ across smoking strata after adjusting for covariates. Estradiol did moderate the relationship between homocysteine and smoking status. This suggests that smoking may have long-term negative effects on homocysteine levels with estradiol exacerbating this relationship particularly in current smokers, hence, the importance of programs to prevent smoking initiation and close monitoring of estradiol levels in current smokers who are also on hormone replacements or who are obese.