Lewis Smith

Publications (2)0 Total impact

• Article: Serum adiponectin is positively associated with lung function in young adults, independent of obesity: The CARDIA study

  Bharat Thyagarajan, David Jacobs, Lewis Smith, Ravi Kalhan, Myron Gross, Akshay Sood
  [show abstract] [hide abstract]
  ABSTRACT: Abstract Rationale Adipose tissue produces adiponectin, an anti-inflammatory protein. Adiponectin deficiency in mice is associated with abnormal post-natal alveolar development. Objective We hypothesized that lower serum adiponectin concentrations are associated with lower lung function in humans, independent of obesity. We explored mediation of this association by insulin resistance and systemic inflammation. Methods and Measurements Spirometry testing was conducted at years 10 and 20 follow-up evaluation visits in 2,056 eligible young adult participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Body mass index, serum adiponectin, serum C-reactive protein (a marker of systemic inflammation), and insulin resistance were assessed at year 15. Main Results After controlling for body mass index, years 10 and 20 forced vital capacity (FVC) were 81 ml and 82 ml lower respectively (p = 0.004 and 0.01 respectively) in the lowest vs. highest adiponectin quartiles. Similarly, years 10 and 20 forced expiratory volume in one second (FEV1) were 50 ml and 38 ml lower (p = 0.01 and 0.09, respectively) in the lowest vs. highest adiponectin quartiles. These associations were no longer significant after adjustment for insulin resistance and C-reactive protein. Serum adiponectin was not associated with FEV1/FVC or peak FEV1. Conclusions Independent of obesity, lower serum adiponectin concentrations are associated with lower lung function. The attenuation of this association after adjustment for insulin resistance and systemic inflammation suggests that these covariates are on a causal pathway linking adiponectin and lung function.
  Respiratory Research. 01/2010;
• Article: Longitudinal association of body mass index with lung function: The CARDIA Study

  Bharat Thyagarajan, David Jacobs, George Apostol, Lewis Smith, Robert Jensen, Robert Crapo, Barr R Graham, Cora Lewis, Williams O Dale
  [show abstract] [hide abstract]
  ABSTRACT: Abstract Background Lung function at the end of life depends on its peak and subsequent decline. Because obesity is epidemic in young adulthood, we quantified age-related changes in lung function relative to body mass index (BMI). Methods The Coronary Artery Risk Development in Young Adults (CARDIA) study in 1985–86 (year 0) recruited 5,115 black and white men and women, aged 18–30. Spirometry testing was conducted at years 0, 2, 5 and 10. We estimated 10 year change in FVC, FEV₁and FEV₁/FVC according to baseline BMI and change in BMI within birth cohorts with initial average ages 20, 24, and 28 years, controlling for race, sex, smoking, asthma, physical activity, and alcohol consumption. Measurements and Main Results Participants with baseline BMI < 21.3 kg/m²experienced 10 year increases of 71 ml in FVC and 60 ml in FEV₁and neither measure declined through age 38. In contrast, participants with baseline BMI ≥ 26.4 kg/m²experienced 10 year decreases of 185 ml in FVC and 64 ml in FEV₁. FEV₁/FVC increased with increasing BMI. Weight gain was also associated with lung function. Those who gained the most weight over 10 years had the largest decrease in FVC, but FVC increased with weight gain in those initially thinnest. In contrast, FEV₁decreased with increasing weight gain in all participants, with maximum decline in obese individuals who gained the most weight during the study. Conclusion Among healthy young adults, increasing BMI in the initially thin participants was associated with increasing then stable lung function through age 38, but there were substantial lung function losses with higher and increasing fatness. These results suggest that the obesity epidemic threatens the lung health of the general population.
  Respiratory Research. 01/2008;