When Sherry Zorzi first picked up a cigarette as a teenager, she never dreamed that one day she’d be telling people not to smoke.

“Back then, it just seemed like an adult thing to do,” she says. “Most of my friends gave it up after a few years, but I was addicted.”

After her decade-older sister — also a longtime smoker — was diagnosed with chronic obstructive pulmonary disease in 2000, Sherry got scared. “I thought, ‘That...