In bucolic Lancaster County, Pa., the Amish grow their own tobacco. In keeping with traditional gender roles, the men smoke the tobacco in cigars, pipes or cigarettes, while the women largely tend to abstain.
A recent study of the Old Order Amish community by University of Maryland researchers has nonetheless found the women to be just as susceptible to the health problems related to exposure to secondhand smoke.
It turned out that the male smokers were potentially harming the women by smoking.
The study by Robert M. Reed, a University of Maryland associate professor of medicine, found that exposure to even low amounts of secondhand smoke impaired the lung function of Amish family members, particularly the nonsmoking women, in a small but measurable way.
Reed said Amish men typically gather on Sundays to smoke, so he wasn't sure he would find anything noteworthy because the amount of secondhand smoke Amish families were exposed to was likely very low.
"It was surprising that we found anything at all, and I think that this really tells us how detrimental secondhand smoke can be," said Reed, who is also a pulmonary and critical care specialist at University of Maryland Medical Center. "I think there are some open questions of the certainty to which we can say that secondhand smoke exposure causes some things like obesity or diabetes, or a lower lung function. And I think our study tips the scale to make it more clear that those are also some of the ill effects."
The study was published in the medical journal PLOS ONE in March.
The researchers examined data on a cross-section of 3,568 Amish who participated in three community surveys of cardiovascular health between 2001 and 2015, according to the University of Maryland Medical System. The data included tobacco use and secondhand smoke exposure from family members.
Because the researchers had records of familial relations in the community, they were able to determine which people had a father, brother or husband who smoked and thus conclude who might have been exposed to secondhand smoke. The researchers also tested lung function and took blood samples.
The researchers did not have to account for potential smoke exposure in the womb since women in the Amish community generally do not smoke. About a third of Amish men in the study smoked, with 64 percent smoking cigars, 46 percent smoking cigarettes and 21 percent smoking pipes. Reed said cigar and pipes produce more noxious secondhand smoke than cigarettes.
Reed said the team used liaisons who work with the Amish community. Other medical researchers have studied the Amish because their lifestyles allow for scientists to control for fewer variables.
"There have been a lot of studies on the effects of secondhand smoking," Reed said. "But a lot of those studies have been kind of difficult to tease out what's a true affect of the smoking and what may be related to other factors that are associated with the behavior of smoking," such as socioeconomic status.
The Amish, he said, are more physically active than the average American, they eat more fruits and vegetables, they largely live in rural areas, and they generally have a similar diet.
Reed found that women who were exposed to secondhand smoke had a higher body mass index on average. Their LDL or "bad" cholesterol was higher, while their HDL or "good" cholesterol was lower. Their fasting glucose levels, an indicator of metabolic health, were also higher among those who had been exposed to secondhand smoke.
"I would not have expected to see such dramatic effects with these low exposures," said Braxton D. Mitchell, the study's senior author and a professor of medicine, epidemiology and public health at the University of Maryland School of Medicine, in a prepared statement.
The researchers assigned each person a point for every nuclear family member who was a smoker, and the women with more family members who smoked had poorer metabolic health markers overall.
Men who were nonsmokers but who had been exposed to secondhand smoke also were more likely to be heavier, have higher LDL cholesterol and have higher fasting glucose readings. Reed found a reduction in lung function of about 2.7 percent for women who had been exposed to secondhand smoke.
Some 480,000 Americans die each year from smoking-related causes, with about 41,000 of those suffering from lung cancer and coronary heart disease related to secondhand smoke exposure, according to a 2014 report by the Office of the Surgeon General. Previous studies have established stroke, lung cancer and coronary heart disease as associated with secondhand smoke exposure.
Some 58 million people in the United States were exposed to secondhand smoke in 2012, the latest year for which data is available, according to the Centers for Disease Control and Prevention, although that number has been cut in half since 2000. Exposure was higher for children, black people, renters and those living in poverty.
"Although we know the dangers, there still are many people who are not protected from smoke," said Brian King, deputy director of research translation for the CDC. "The finding from this study and other studies reinforce that secondhand smoke is bad, there's no safe level of exposure and that even brief exposure can have immediate adverse impacts on your health."
The surgeon general's current report on secondhand smoke "expresses some doubt as to whether certain things like lung function is worse in relation to secondhand smoke exposure," according to Reed, the lead researcher.
"I think our study adds some clarity to that question," he said, "because we did find a small but detectible reduction in lung function."
Kirsten Koehler, an assistant professor at the Johns Hopkins Bloomberg School of Public Health, said the study's findings, while not groundbreaking, added to the body of knowledge about the harmful effects of secondhand smoke.
"I don't know that it added much that was that new, but it added a group of understudied people," Koehler said. "It contributes to the evidence base for what we know about secondhand smoke."
But Mark Geraci, the chair of medicine at Indiana University, said many people aren't aware of how dangerous secondhand smoke is and that more research like Reed's is needed to quantify it.
"I think most people would argue that smoking is bad for you, but actual data on secondhand smoke is still evolving," Geraci said. "There are many individuals and groups that aren't sure what the detrimental effects of secondhand smoke are. It's difficult to quantify exposure to secondhand smoke. I think that is an area where there's a tremendous need for experimentation."