Metabolic abnormalities in children with asthma

Abstract

Rationale: Childhood asthma and obesity have reached epidemic proportions worldwide, and the latter is also contributing to increasing rates of related metabolic disorders, such as diabetes. Yet, the relationship between asthma, obesity, and abnormal lipid and glucose metabolism is not well understood, nor has it been adequately explored in children.

Objectives: To analyze the relationship between asthma diagnosis and body mass in children across the entire range of weight percentile categories, and to test the hypothesis that early derangement in lipid and glucose metabolism is independently associated with increased risk for asthma.

Methods: Cross-sectional analysis of a representative sample of public school children from a statewide community-based screening program, including a total of 17,994 children, 4 to 12 years old, living in predominantly rural West Virginia, and enrolled in kindergarten, second, or fifth grade classrooms.

Measurements and main results: We analyzed demographics; family history; smoke exposure; parent-reported asthma diagnosis; body mass index; evidence of acanthosis nigricans as a marker for developing insulin resistance; and fasting serum lipid profile including total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. Regardless of their body mass index percentile, children diagnosed with asthma were more likely than children without asthma to have higher triglyceride levels and acanthosis nigricans after controlling for sex differences and smoke exposure.

Conclusions: This study provides the first set of community-based data linking asthma, body mass, and metabolic variables in children. In particular, these findings uniquely describe a statistically significant association between asthma and abnormal lipid and glucose metabolism beyond body mass index associations.

Figure 1.

Asthma prevalence based on weight category. As a general trend, asthma prevalence increased as children's body mass index percentile increased. Asthma prevalence in children who are obese and morbidly obese was significantly higher than in children with healthy body mass index, whereas simple overweight status did not increase this risk. Asthma patterns in children who are obese were similar for males and females and across grades.

Figure 2.

Metabolic variables based on weight category. Mean serum levels for total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TRIG) (A) and prevalence of acanthosis nigricans (AN) (B) distributed by body mass index percentile. Whereas the serum levels for TC and LDL increased only slightly going from overweight to obese, and actually decreased going from obese to morbidly obese, serum TRIG and AN prevalence increased progressively and significantly as the body mass index category increased.

Figure 3.

Metabolic variables based on asthma status. Proportion of children with dyslipidemia according to age-specific reference values (20) for total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TRIG) (A), and proportion of children with evidence of acanthosis nigricans (AN) (B) based on the presence or absence of asthma diagnosis. Serum TRIG and AN were found to be independently associated with asthma regardless of weight status and after controlling for sex and smoking status.

Figure 4.

Relationships between asthma and metabolic dysfunction. Hierarchical linear regression model predicting serum triglyceride levels (A) and binary logistic regression predicting the presence of acanthosis nigricans (AN) (B) based on the diagnosis of asthma. Asthma diagnosis continued to be significantly associated with both hypertriglyceridemia and AN after controlling for sex, smoke exposure, and body mass index (BMI) percentile.