Secondhand smoke exposure during childhood may change cholesterol levels in a way that could increase the risk for heart disease later in life. That risk may not be the same for both genders.
A recent study tested cholesterol levels in a group of 17-year-olds to see if secondhand smoke exposure in the home for 17 years could lower good cholesterol levels and increase the risk for future heart disease.
The results of the study showed that girls, in particular, who had been exposed to secondhand smoke in the home had lower levels of good cholesterol—a possible risk factor for heart disease.
Chi Le-Ha, MD, from the School of Medicine and Pharmacology at the University of Western Australia in Perth, Australia, led an investigation into cholesterol changes in teenage boys and girls from secondhand smoke exposure throughout childhood.
Previous studies have shown links between secondhand smoke exposure and heart disease. Unfavorable cholesterol levels are a known risk factors for heart disease.
High-density lipoprotein (HDL) cholesterol is sometimes referred to as “the good cholesterol.” Higher HDL cholesterol levels may help reduce the risk for heart disease by picking up extra cholesterol in the blood stream and transporting it to the liver for processing.
For this study, 804 non-smoking 17-year-olds in an ongoing study were asked about their exposure to cigarette smoke in their homes from the time of their mother’s pregnancy through present day.
The researchers took blood samples and measured HDL cholesterol levels in each individual.
Further blood tests, weight, alcohol consumption, diet and other lifestyle risk factors for heart disease were taken into account for each participant.
“From birth to 17 years, 48 percent of the sample had been exposed to passive (secondhand) smoking in the household,” the study authors said.
After adjusting for lifestyle risk factors, the researchers found that HDL cholesterol levels were lower in girls who were exposed to secondhand smoke compared to boys.
On average, the girls in the study who had been exposed to secondhand smoke for 17 years in the home had HDL cholesterol levels 0.094 mmol/L lower than girls who had not been exposed to secondhand smoke.
To put this number into perspective, the researchers compared it to monitored levels of HDL cholesterol in the famous Framingham Heart Study, which showed an increase of 0.026 mmol/L in HDL cholesterol to lower the risk of heart disease by 3 percent in women.
The authors concluded that girls exposed to secondhand smoke while they were growing up could have a greater risk for heart disease later in life.
The authors recommended further efforts to reduce children’s exposure to secondhand smoke.
This study was published in April in the Journal of Clinical Endocrinology & Metabolism.
This research was funded by the NH&MRC, the Raine Medical Research Foundation, the Telethon Institute for Child Health Research, the Women and Infants Research Foundation, Curtin University and an award from the Australian Government. No conflicts of interest were declared.