One third of the world's smokers live in China, so any effective policy reducing Chinese smoking could have enormous health impacts, even globally. The WHO reported in 2011 that there were many opportunities to curb tobacco use, opportunities which researchers put to the test. (Photo : Reuters)

Teenage girls exposed to secondhand smoke at home tended to show lower levels of the “good” form of cholesterol known to reduce heart disease risk, reports a study to be published in The Endocrine Society’s Journal of Clinical Endocrinology and Metabolism.

The same trend was not exhibited in teenage boys, however, report the study’s lead author Dr. Chi Le-Ha, of the University of Australia.

The finding is especially significant, Le-Ha said, given that cardiovascular disease is the leading cause of death in women in the Western world.

“Good” cholesterol, known as high-density lipoproteins (HDL), are responsible for picking up excess cholesterol in the blood stream and transporting it to the liver where it can be broken down.

Low-density lipoproteins (LDL), on the other hand, can create a waxy build-up that blocks blood vessels.

For this reason, HDL is considered key in combating heart disease risk.

To come to their conclusion, the researchers studied a longitudinal birth cohort of 1,057 adolescents born between 1989 and 1992 in Perth, Australia and information about smoking in the household starting at 18 weeks gestation until 17 years old. The scientists then performed blood tests to determine the teenagers’ cholesterol levels.

In all, 48 percent of those studied were exposed to secondhand smoke at home.

“The findings indicate childhood passive smoke exposure may be a more significant cardiovascular risk factor for women than me,” Le-Ha said in a press release regarding the study.

For this reason, the researcher said the study indicates a need “to redouble public health efforts to reduce young children’s secondhand smoke exposure in the home, particularly girls’ exposure.”

Other researchers included L.Beilin, S. Burrows, R. Huan, W. Oddy and T. Mori of the University of Western Australia and B. Hands of Notre Dame University in Perth, Australia.