Obesity and Asthma: Is There a Link?

Research is providing us with clear evidence that asthma is linked to obesity in many cases. Let’s look at the evidence.

Asthma basics

Currently about 72 million Americans—nearly one-third of the population—are obese according to the 2005-2006 National Health and Nutrition Examination.

Research also finds that obesity is irrefutably tied to asthma: An asthmatic is more likely to be obese, and an obese person is more likely to be asthmatic.

Obesity rates have increased with the increase in asthma among industrialized countries. For example, researchers from Sweden’s Uppsala University (Uddenfeldt et al. 2010) found in their 13-year study of 8,150 people that obesity increased the risk of adult-onset asthma by 49%, and weight loss prevented asthma episodes.

Scientists from the Centers for Disease Control and Prevention (CDC 2009) determined that preschool obese children are more likely to contract asthma, and children who are obese during their preschool years have a greater likelihood of being obese during teenage and adult years.

Greece researchers from the Penteli Children’s Hospital (Priftis et al. 2007) studied 700 children between 10 and 12 years old. Asthma symptoms were found in 28% of the boys and 20% of the girls. The researchers also found that higher body weight and sedentary activity was associated with higher levels of asthma. This association was especially apparent among the boys.

Researchers from Canada’s Ottawa Hospital (Pakhale et al. 2010) found, in a study of 496 adults with diagnosed asthma, that obese asthmatics have worse lung function and more fatalities than do normal-weight asthmatics.

Included in the study group were 242 obese and 254 normal-weight persons. More men were obese than women. The asthmatic men were also more likely to have high blood pressure and gastroesophageal reflux disease (GERD); as well as reduced lung function. They also found, as mentioned earlier, that obese persons with lower lung function who saw a doctor were also more likely to be misdiagnosed with asthma.

Iranian researchers (Ziaei Kajbaf et al. 2011) polled 903 Iranian children ages 7 to 11 years old using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. They compared responses with height and weight scores using body mass index (BMI). Of the total population, 22% were currently wheezing. However, 69% of the obese children had current wheezing and 37% of the overweight children had current wheezing. In other words, obesity increased the rate of wheezing by three times.

Researchers from Montreal’s Behavioural Medicine Centre and the Hospital Sacré-Cœur (Wright et al. 2010) studied 673 adult asthmatics. They found that overweight individuals were 95% more likely to have asthma triggered by exercise (EIA). Those with lower BMI (body mass index) had significantly fewer asthmatic flare-ups from exercise.

Researchers from the University of Wisconsin (Zhang et al. 2010) studied the weight of children in relation to asthma utilizing the Childhood Origin of Asthma project. They followed 285 full-term newborns from birth to five years of age, and then followed up by studying their asthma incidence at six years old and eight years old. Those children not overweight at one year old who became overweight by age five had higher rates of asthma.

Researchers from the University of Texas (Peters et al. 2011), after studying 902 child and adult asthma patients, found that obesity was associated with lower forced vital capacity. The higher the BMI, the more reduced the forced vital capacity.

Kansas State University researchers (Rosenkranz et al. 2010) found similar correlations as they studied 40 young children, comparing their weight in body mass index along with their relative lung capacities. They found that the higher the BMI, the lower the FEV1 (forced expiration volume in one second) levels.

Department of Pediatrics, researchers from University of Eastern Finland’s School of Medicine (Sidoroff et al. 2010) studied childhood wheezing rates in a group of 100 children hospitalized for wheezing-related infections. As they studied the group over the years—from less than two years old up to 12 years old—they found that greater BMI levels during these years resulted in significantly lower levels of FEV1/FVC ratios (forced expiratory volume in one second divided by forced vital capacity). They also found that maximal expiratory flows were significantly lower among children with greater BMIs.

Respiratory researchers from Catholic University in Rome (Corbo et al. 2008) studied 20,016 children between the ages of six and seven years old. Using population multivariate analysis, they determined that the greatest factors for developing asthma and wheezing were obesity, TV viewing and poor dietary habits.

Out of the total population, they found that 8% of the children had current wheezing and 6.7% had current asthma. Elevated weight—measured by body mass index—equated to significantly higher levels of both wheeze and asthma. Children who watched television for five or more hours every day also had higher rates of wheeze and asthma, as compared to children who watched one hour of television per day. They also found that heavily-salted diets increase the likelihood of asthma and wheeze.

Asthma and metabolic syndrome

Obesity is also associated with a disorder now called metabolic syndrome. According to the American Heart Association, metabolic syndrome is related to the following conditions:

–      Blood sugar issues (diabetes, insulin resistance, hypoglycemia)

–      Obesity (most specifically abdominal obesity)

–      Cholesterol issues (high LDL, low HDL, high triglycerides)

–      High blood pressure

–      Chronic inflammation markers (including C-reactive protein, high white blood cell count, high eosinophils)

–      Atherosclerosis (damage and hardening to the arteries—indicated by fibrinogen, circulation problems and so on.)

Metabolic syndrome is characterized by cholesterol problems, high blood pressure, diabetes or hypoglycemia, chronic inflammation, cardiovascular disease and heart disease. All of these issues add up to the same issue: systemic inflammation. Furthermore, each of these conditions have the same underlying issues: Poor dietary choices, high levels of reactive oxygen species, increased infections, an overburdened immune system, lack of exercise and other poor lifestyle choices.

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