Weight Gain After Stopping to Smoke Doesn’t Overly Raise Disease Risk, Study Says

Joana Carvalho, PhD avatar

by Joana Carvalho, PhD |

Share this article:

Share article via email
smoking and risk

Weight gain after stopping to smoke tobacco does not significantly minimize for men the protection that smoking is thought to bring against a likelihood developing Parkinson’s disease, according to a Korean nationwide study.

“These findings indicate that smoking may be a much more powerful factor than weight gain” in terms of disease risk, its researchers wrote.

The study, “Smoking Cessation, Weight Change, and Risk of Parkinson’s Disease: Analysis of National Cohort Data,” was published in the Journal of Clinical Neurology.

Although the specific causes underlying Parkinson’s are still not fully understood, it is believed this neurodegenerative disease results from a combination of genetic and environmental factors.

Cigarette smoking is thought to reduce the risk of Parkinson’s in both current and former smokers. One study found a 58% lower disease risk in current smokers, and a 24% lower risk in former smokers, than was evident in people who had never smoked.

At the same time, smoking cessation is steadily increasing worldwide, and “is associated with substantial health benefits for smokers, but subsequent weight gain is of concern in those who attempt to quit smoking.”

Weight gain usually occurs in the months following smoking cessation, and in some cases persists for long periods. This can be problematic not only because excessive weight can negative affect the body’s metabolism, but also because it is associated with a greater Parkinson’s risk.

“Thus, we hypothesized that weight gain following smoking cessation offsets the benefit of smoking on PD [Parkinson’s disease] risk,” the researchers wrote.

They reviewed the medical records of 3.91 million Korean men, ages 40 and older, who underwent at least two health checkups every other year between 2009 and 2015. Records came from the Korean National Health Insurance Service (KNHIS) database.

Men included in the study were followed from their second health checkup through December 2017, or until their death.

Investigators divided men into five groups, depending on their smoking and weight status: current smokers, never smokers, quitters who experienced weight gain, quitters whose body weight remained the same, and quitters who lose weight.

A total of 6,871 individuals developed Parkinson’s during the years of follow-up.

At the second health checkup, more than half (52.7%) of the men were current smokers, and around a third (38.5%) had never smoked. Among those who quit smoking (9%, 344,173 people), most maintained their original body weight (67%) while 26% gained weight.

Compared with men who never smoked, current smokers had the lowest risk of developing Parkinson’s (39% less), followed by quitters (22% less).

Among quitters, the risk of Parkinson’s dropped by at least 20% among those who either maintained or gained weight, compared with those who had never smoked. A similar tendency was also seen in the group of quitters who lost weight.

When investigators assessed the overall impact of body weight changes on Parkinson’s risk regardless of smoking status, they found that weight gain, but not weight loss, was linked with a greater disease likelihood.

“In conclusion, this national cohort big-data analysis has demonstrated that the protective effect of smoking on PD [Parkinson’s disease] development tends to persist in males regardless of their post-cessation weight gain or maintenance,” the researchers wrote.

Study evidence indicates that “post-cessation weight change is not expected to significantly alter the PD risk in individuals with a smoking history,” they added.

A study weakness, however, was its relatively short follow-up period, and findings should be interpreted with caution.

“Further research with a longer follow-up could help to confirm the impact of post-cessation weight change on the risk of PD,” the team concluded.