Smoking is the leading cause of chronic obstructive pulmonary disease (COPD) in the US, where cigarettes cause up to 80-90% of all COPD cases..

The remaining 10-20%, according to doctors, may be due to air pollution and genetic factors..

A new study published in the British Medical Journal suggests malnutrition may be an underreported but very important risk factor for COPD..

The group of chronic obstructive pulmonary diseases includes such serious diseases as chronic bronchitis and emphysema..

These diseases cause airway obstruction and breathing problems.

Symptoms of COPD may include shortness of breath, chronic cough, frequent respiratory infections, excessive sputum production, fatigue.

US health experts estimate that COPD affects 12.7 million people over the age of 18 in the United States.. Chronic lung disease was responsible for 134,676 deaths in this country in 2010, ranking third behind cardiovascular disease and cancer.

Everyone has long known that COPD is a disease of smokers.. But the authors of the new study, renowned scientists from France and the US, say we underestimate other modifiable risk factors.. They claim that diet is the most important of them after smoking.. But, unfortunately, science knows very little about the relationship between nutrition and COPD..

In an effort to fill this important gap, an international team of researchers decided to analyze the risk of COPD in 73,228 women who participated in the National Nurses' Health Study, conducted from 1984 to 2000 in the United States..

The male cohort of 47,206 participants was drawn from the Health Professionals Follow-Up Study (1986-1998) of American physicians..

A healthy diet reduces the risk of COPD by a third.

Prior to the start of each study, all participants were asked to complete a questionnaire that included dietary habits, as well as body weight, physical activity, smoking, disease, and other risk factors..

After the start of the work, participants re-filled questionnaires every 2 years, through which scientists could learn about changes in the lifestyle and health status of doctors and nurses..

Participation in both studies of medical workers allows us to hope for a high level of reliability of the data obtained and makes them a valuable source of information for scientists..

A few facts about COPD:.

- In 2010, direct and indirect US losses due to COPD amounted to $49.9 billion.

- In the United States, in addition to 12.7 million people with COPD, there are 24 million people with significant impairment of lung function. This suggests that the number of patients is greatly underestimated..

- Women who smoke are almost 13 times more likely to die from COPD than women who have never smoked. Men who smoke are 12 times more likely to die from COPD than non-smokers..

To assess the quality of nutrition of participants, the authors of the latest work used the Alternate Healthy Eating Index 2010 scale (AHEI-2010).

A high AHEI-2010 score indicates that the participant eats well, eats a lot of vegetables, fruits and whole grains, polyunsaturated fatty acids, nuts, omega-3 fatty acids. A low score indicates a low content of healthy foods and a large amount of red meat, animal fats, easily digestible carbohydrates, and alcohol..

During the follow-up period, 167 new cases of COPD were reported in both studies in men and 723 new cases in women..

Researchers found that participants with the highest AHEI-2010 score had a 1/3 lower risk of developing COPD compared to participants with the lowest score. This suggests that a healthy diet may protect against COPD..

The results of the analysis remained significant even after introducing factors such as body mass index (BMI) of participants, smoking, race, nationality, age, and socioeconomic characteristics.

“Physicians should consider the role of diet in the development of lung disease. Our data suggest that antioxidants in a healthy diet may protect the lungs. Since the lungs exist in constant contact with oxygen, it is reasonable to assume that inflammation and some other destructive processes proceed more intensively if there is not enough antioxidants.. A balance between potentially harmful substances and antioxidant defenses, including beneficial substances from food, is important for COPD prevention and lung protection,” the authors write..

Scientists acknowledge their study had some limitations.

For example, all participants in the work are medical workers.

They may be more health conscious and make better decisions, have higher socioeconomic status, smoke less frequently, so their results may not be applicable to the general population.

In addition, the vast majority of study participants were white, non-Hispanic - in the US, this also matters for health.

medbe. en.