Multiple sclerosis (MS) is an autoimmune disease that targets the myelin sheath (fatty coating) that surrounds and protects your central nervous system (brain and spinal cord). While the cause of MS is not well understood, environmental factors such as smoking — including a person’s exposure to secondhand smoke in childhood — have been found to play a significant role in the development of MS.

Secondhand smoke contains 7,000 chemicals that can be detrimental to a developing child’s health and can contribute to many chronic conditions. A 2020 study from Denmark’s Ryshospitalet of 4,328 Scandinavians found that children who were consistently exposed to secondhand smoke had an increased risk of developing MS later in their lives. The risk was higher for females at 43 percent; for males. it was 23 percent.

This article will discuss the dangers of secondhand smoke, how exposure can make a child susceptible to MS, and how you can set up a smoke-free environment to keep children safe.

The Dangers of Secondhand Smoke

Public policy, education, and a cultural attitude shift on the popularity of smoking has drastically reduced the number of adults who smoke in the U.S. In fact, in 2018, the percentage of the American population who smoked reached an all-time low: 13.7 percent. Still, in 2019, nearly 1 in 7 adults continued to smoke cigarettes. And between 2017 and 2018, the use of e-cigarettes (vaping) increased by 3.2 percent in adults aged 18 and up. That means children today are susceptible not only to tobacco smoke exposure, but also to the high levels of nicotine found in the aerosol (vapor) produced from vape pens.

The short- and long-term health consequences of a child’s exposure to secondhand smoke (also called passive smoking) are extensive. Such exposure can lead children to experience:

• Multiple sclerosis
• Lung cancer
• Lung disease
• Cardiovascular (heart) disease
• Respiratory issues
• Frequent cough, colds, and ear infections
• Tooth decay

The link to poor health stemming from childhood exposure to secondhand tobacco smoke is well-known. But exactly how the chemicals in that smoke lead to the breakdown of a person’s myelin and them developing MS symptoms is still being determined. Experts have narrowed in on a few possible causes.

Childhood Exposure and the Pathway to MS

Researchers have shown that a combination of genetic and environmental factors are likely culprits in the demyelination (loss of a nerve’s fatty outer sheath) that people with MS experience. The chemicals found in secondhand smoke — nitrous oxide and cyanide — can provoke a cascade of internal reactions that contribute to a person’s myelin and nerve fibers breaking down. This disintegration can cause people to have issues with mobility, fatigue, vision, numbness, dizziness, and spasticity, among other concerns.

Regular exposure to secondhand smoke has also been found to alter a person’s immune system, thus allowing infections into their body. A compromised immune system and contracting certain viral infections are the suspected leading causes of MS — and many other nervous system disorders, too.

Immune System Function

Cigarette smoke has been found to disturb the function of a person’s immune system. It does this by altering important white blood cell functions that are critical to your body’s natural defense against infection and disease. When your body’s defensive system is compromised, you are more susceptible to dangerous environmental factors — the very things your immune system tries to protect you from.

Epstein-Barr Virus

The majority of people diagnosed with MS have been found to have a current or prior infection with the Epstein-Barr virus (EBV). That finding has led experts to believe that being infected by EBV may be a risk factor for developing MS. (EBV is one of the most common human viruses globally. Most who are infected with it will not have any symptoms.)

Here’s how it is thought to happen: When it’s first contracted, EBV initially causes some people — not the majority — to have mononucleosis or “mono”. (Mono typically affects teens and adults younger than 35 — and only 25 percent of that total group — who have not yet built up antibodies to EBV like the general adult population.) After mono has run its course, EBV typically stays latent within your body, waiting to be reactivated. Studies have shown that smoking could reactivate EBV, which would put a person at a higher risk of developing MS.

Setting Up a Smoke-Free Environment

Smoking is a hard habit to break. And it can be difficult to limit anyone’s environmental exposure to secondhand smoke. The American Academy of Pediatrics understands this twofold challenge.

They recommend some of the following tips to set up a smoke-free environment for both adults and children:

• Support household members and caregivers as they quit smoking.
• Eliminate smoking in your house and car.
• Hire nonsmoking childcare providers and babysitters.
• Remove your child from settings that allow smoking.
• Encourage your community schools to be tobacco-free.

Secondhand smoke is dangerous for any child’s health and well-being. And now its link to an increased risk of MS makes eliminating children’s exposure to secondhand smoke even more critical for their health.

Talk With Others Who Understand

On MyMSTeam, the social network for people living with multiple sclerosis and their loved ones, more than 179,000 members come together to ask questions, give advice, and share their experiences with others who understand life with MS.

Were you exposed to secondhand smoke as a child? Do you have a child in your family or household who is currently exposed to it? Share your experience in the comments below or by starting a discussion on MyMSTeam.