Worsening Asthma Tied to Sausage and Ham

Results from a 7-year prospective study of 971 French adults showed a clear link between cured meat intake and worsening asthma symptoms (multivariable OR 1.76, 95% CI 1.01-3.06 for ≥4 versus <1 serving/week), reported Zhen Li, MD, of Inserm, Paul Brousse Hospital in Villejuif, and colleagues.

In addition, body mass index (BMI), which has previously been associated with exacerbating asthma symptoms, accounted for just 14% of the total effect (OR 1.07; 95% CI 1.01-1.14), they wrote online in Thorax.

“This research extends the deleterious effect of cured meat on health, and the effect of diet on asthma in adults, and provides a novel analytic approach regarding the role of BMI in the diet-asthma association,” the authors noted.

“Besides our finding on the association between cured meat and worsening asthma symptoms, cured meat intake has also been linked to increased risk of many other chronic diseases, including cancer, cardiovascular diseases, type 2 diabetes, and [chronic obstructive pulmonary disorder], and was recently classified as carcinogenic by the World Health Organization,” Li told MedPage Today.

Li’s group analyzed data from the French Epidemiological study on the Genetics and Environment of Asthma (EGEA) — a longitudinal study that followed a group of asthma cases, their first-degree relatives, and controls for 20 years — to evaluate the link between processed meat intake and worsening of asthma symptoms among 971 adults (49% men). The average age of participants was 43 and 42% had asthma.

BMI at EGEA2 was categorized into five classes: <22.5, 22.5–24.9, 25–27.4, 27.5–29.9, and ≥30.

Dietary intake was measured via food frequency questionnaires with 118 items in 46 food groups. Cured meat intake (ham, sausage, salami) was classified as low for one or fewer weekly servings, medium for one to four weekly servings, and high for four or more. Asthma symptoms — such as difficulty breathing, chest tightness, and shortness of breath in the preceding 12 months — were scored from zero to five.

The researchers also collected data on other potentially influential factors, such as smoking, regular physical activity, age, sex, and education.

Using mediation analysis in the counterfactual framework, the researchers found a positive association between high intake of cured meat and worsening asthma symptoms over time.

From 2003 to 2007, 42% of the participants said they had asthma at some point, with one in five (20%) participants reporting that their symptoms had worsened by 2011-2013.

The researchers also found that the proportion of adults with worsening asthma symptoms varied by weekly cured meat intake: 14% among those who ate one or fewer weekly servings, 20% among those who ate one to four, and 22% among those who consumed four or more.

After accounting for potential confounders, “the highest likelihood (76% more) was observed among participants who ate cured meats four or more servings per week, compared with those who ate less than one serving per week,” Li told MedPage Today.

Overweight and obesity, which have previously been associated with aggravating asthma, accounted for just 14% of this association, “suggesting a deleterious role of cured meat independent of BMI.”

The study had several limitations, including the observational nature of the study which may have hindered their ability to draw firm conclusions about cause and effect.

Additionally, the survey responses relied on memory and the symptom score may have been affected by smoking or by COPD, a chronic lung disease that shares many of its symptoms with asthma.

Li said that he hoped findings such as these would lead to public health initiatives regarding cured meat intake. “There remains a gap regarding the spread of knowledge from the research community to [the] public,” he sated. “Public health strategies are warranted to reduce cured meat/processed meat intake, and there is nothing to be lost by acting now.”

• Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner