Faculty Bibliography

Early stress exposure is proposed to have significant lasting effects on cognitive development. The glucocorticoid hormone cortisol, a product of the hypothalamic-pituitary-adrenal (HPA) axis, is a particular focus of research, however, the majority of past research has been based on studies of older children and adults. Evidence linking cortisol levels in infancy with cognitive development is lacking. In a large cohort sample of infants (N = 1,091) oversampled for psychosocial risk, we tested whether basal cortisol levels and cortisol reactivity to emotional stressors administered at 7 and 15 months of age were associated with cognitive development measured at 15 months. Cognitive development was measured using the Mental Development Index of the Bayley Scales of Infant Development. Multiple regression analyses indicated that basal cortisol levels at 15 months, and to a lesser extent at 7 months, were inversely associated with infant cognitive development after adjusting for psychosocial and obstetric risk. The findings provide some of the first evidence that HPA axis activity in infancy is associated with early cognitive development.

INTRODUCTION: Waterpipe smoking has become increasingly popular in adolescents. We examined the association of waterpipe smoking with cigarette smoking susceptibility and nicotine dependence among adolescents in Hong Kong. METHODS: We analyzed the data of School-based Survey on Smoking among Students 2012/13 from a representative sample of 45,857 secondary school students (US grades 7-12) in Hong Kong. Among never cigarette smokers (n=37,740), we conducted chi-square test to compare cigarette smoking susceptibility by current (past 30-day) waterpipe smoking status, and used multivariate logistic regression to examine the association between current waterpipe smoking and cigarette smoking susceptibility controlling for age, sex, peer cigarette smoking, and living with a cigarette smoker. Then we conducted chi-square test and multivariate logistic regression among current cigarette smokers (n=1694) to examine the relationship of current waterpipe smoking with two nicotine dependence outcomes, including heavier smoking (>/=5 cigarettes/day) and first cigarette within 30min of waking, controlling for demographics and the number of smoking days in the past 30days. RESULTS: Among never cigarette smokers, current waterpipe use was associated with cigarette smoking susceptibility (adjusted odds ratio [AOR]=3.58, 95% confidence interval [CI]: 1.61-7.97). Of current cigarette smokers, waterpipe use was associated with heavier smoking (AOR=1.56, 95% CI: 1.00-2.43) and first cigarette within 30min of waking (AOR=2.08, 95% CI: 1.35-3.19). CONCLUSIONS: Surveillance, prevention, and intervention programs should address waterpipe use in addition to cigarette smoking. Educational programs need to inform youth about the harmful and addictive effects of waterpipe smoking. Public health campaigns deglamourizing waterpipe use may help reduce waterpipe smoking among youth.

Few investigations have evaluated the incremental usefulness of tubular injury biomarkers for improved prediction of chronic kidney disease (CKD) progression. As such, we measured urinary kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, N-acetyl-ß-D-glucosaminidase and liver fatty acid binding protein under highly standardized conditions among 2466 enrollees of the prospective Chronic Renal Insufficiency Cohort Study. During 9433 person-years of follow-up, there were 581 cases of CKD progression defined as incident end-stage renal disease or halving of the estimated glomerular filtration rate. Levels of the urine injury biomarkers, normalized for urine creatinine, were strongly associated with CKD progression in unadjusted Cox proportional hazard models with hazard ratios in the range of 7 to 15 comparing the highest with the lowest quintiles. However, after controlling for the serum creatinine-based estimated glomerular filtration rate and urinary albumin/creatinine ratio, none of the normalized biomarkers was independently associated with CKD progression. None of the biomarkers improved on the high (0.89) C-statistic for the base clinical model. Thus, among patients with CKD, risk prediction with a clinical model that includes the serum creatinine-based estimated glomerular filtration rate and the urinary albumin/creatinine ratio is not improved on with the addition of renal tubular injury biomarkers.