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1.  Changing Trends in the Prevalence and Disparities of Obesity and Other Cardiovascular Disease Risk Factors in Three Racial/Ethnic Groups of USA Adults 
Objectives. To examine trends in the prevalence and disparities of traditional cardiovascular disease (CVD) risk factors among the major race/ethnic groups in the USA: non-Hispanic Whites (NHWs), non-Hispanic Blacks (NHBs), and Mexican Americans (MAs). Methods. We used cross-sectional trend analysis in women and men aged 25–84 years participating in the NHANES surveys, years 1988–1994 (n = 14,341) and 1999–2004 (n = 12,360). Results. The prevalence of obesity and hypertension increased significantly in NHW and NHB, both in men and women; NHB had the highest prevalence of obesity and hypertension in each time period. Diabetes prevalence showed a nonsignificant increasing trend in all groups and was higher in MA in both periods. Smoking significantly decreased in NHW men and NHB, the latter with the largest decline although the highest prevalence in each period; no changes were noted in MA, who had the lowest prevalence in both periods. Race/ethnic CVD risk factors disparities widened for obesity and hypercholesterolemia, remained unchanged for diabetes and hypertension, and narrowed for smoking. Conclusions. The increasing prevalence of obesity and hypertension underscores the need for better preventive measures, particularly in the NHB group that exhibits the worst trends. The decline in smoking rates may offset some of these unfavorable trends.
PMCID: PMC3518078  PMID: 23243516
2.  The time burden of overweight and obesity in primary care 
Overweight and obesity are associated with many conditions treated in primary care. Our objectives were: 1) to determine the frequency of weight-related conditions in a national sample of outpatient visits in the United States; 2) to establish the percentage of diagnosis codes and visit codes attributable to overweight and obesity; and 3) to estimate time spent to address these conditions, including time attributable to overweight and obesity itself.
We analyzed primary care visits from the 2005 and 2006 National Ambulatory Medical Care Survey (NAMCS) in the United States. Weight-related conditions included diabetes, hypertension, hyperlipidemia, obesity, cardiovascular disease, osteoarthritis, and low back pain. We used multivariable logistic regression to estimate an odds ratio for each weight-related condition, which we then converted to an attributable fraction (AF). The AF represents the percentage of diagnosis codes and visit codes attributable to excess weight for that condition. We then divided total visit time among all diagnoses and clinical items addressed at the primary care visit. Finally, to calculate the time attributable to overweight and obesity, we multiplied the AFs by the time spent on each weight-related condition.
The total number of clinical items (diagnoses + medications + tests + counseling) was estimated to be 7.6 per patient, of which 2.2 were weight-related. Of a total visit time of 21.77 minutes, time spent addressing weight-related conditions was 5.65 minutes (30%), including 1.75 minutes (8.0%) attributable to overweight and obesity.
Approximately 8% of time from primary care visits is attributable to overweight and obesity. This estimate is conservative because the NAMCS only allows for coding of three diagnoses addressed per visit. Estimates of the time burden of overweight and obesity provide data to prioritize weight management for prevention and treatment.
PMCID: PMC3175444  PMID: 21846407
3.  Early-Life Predictors of Higher Body Mass Index in Healthy Children 
Childhood obesity tracks into adulthood, and may increase diabetes and cardiovascular disease risk in adulthood. Prospective analyses may better define the pathways between early life factors and greater childhood body mass index (BMI), a measure of obesity.
The Diabetes Autoimmunity Study in the Young (DAISY) prospectively follows children from birth that are at increased genetic risk for type 1 diabetes. We examined longitudinal data for 1,178 DAISY subjects (mean age at last follow-up: 6.59 years (range: 2.0–11.5 years). Birth size and diabetes exposure in utero were collected in the enrollment interview. Infant diet information was collected via interviews throughout infancy. Infant weight gain and childhood BMI were measured at clinic visits.
Female gender, diabetes exposure in utero, larger size for gestational age, shorter breastfeeding duration, and more rapid infant weight gain predicted higher childhood BMI. Formal mediation analysis suggests the effect of shorter breastfeeding duration on childhood BMI may be mediated by more rapid infant weight gain. Also, the effect of diabetes exposure in utero on childhood BMI may be mediated by larger size for gestational age.
We identified strong interrelationships between early life factors and childhood BMI. Understanding these pathways may aid childhood obesity prevention efforts.
PMCID: PMC2855270  PMID: 19940472
Breastfeeding duration; Infant weight gain; Diabetes exposure in utero; Birth size; Mediator
4.  Do calorie-controlled portion sizes of snacks reduce energy intake? 
Appetite  2009;52(3):793-796.
In a cross-over study, participants (n=59) were randomly assigned to receive either 100 kcal packs or standard size packages of snacks for 1-week. After a minimum of a 1-week washout period, participants received the other form of the snack for 1 week. Snack consumption was recorded by participants in a diary. Participants consumed an average of 186.9 fewer grams of snacks per week when receiving 100 kcal snack packs compared to standard size packages of snacks. Post-hoc comparisons revealed the effect of package size depended on both randomization order and study week. Total grams of snacks consumed in week 1 differed significantly between the two randomized groups. In week 2, however, grams of snacks did not differ significantly between the two groups. This interaction was primarily due to a significantly lower consumption of snacks from standard size packages in the week following the portion-controlled packages. The results suggest that portion-controlled packaging reduce total intake from the provided snacks. Further, initial exposure to portion-controlled packages might have increased awareness of portion size such that less was consumed when larger packages were available.
PMCID: PMC2694140  PMID: 19501784
Portion size control; snacks; packaging; food intake
5.  Evaluation of Urinary Biomarkers for Coronary Artery Disease, Diabetes, and Diabetic Kidney Disease 
In this study we sought to validate urinary biomarkers for diabetes and two common complications, coronary artery disease (CAD) and diabetic nephropathy (DN).
A CAD score calculated by summing the product of a classification coefficient and signal amplitude of 15 urinary polypeptides was previously developed. Five sequences of biomarkers in the panel were identified as fragments of collagen Α-1(I) and Α-1(III). Prospectively collected urine samples available for analysis from 19 out of 20 individuals with CAD (15 with type 1 diabetes [T1D] and four without diabetes) and age-, sex-, and diabetes-matched controls enrolled in the Coronary Artery Calcification in Type 1 Diabetes study were analyzed for the CAD score using capillary electrophoresis and electrospray ionization mass spectrometry. Two panels of biomarkers that were previously defined to distinguish diabetes status were analyzed to determine their relationship to T1D. Three biomarker panels developed to distinguish DN (DNS) and two biomarker panels developed to distinguish renal disease (RDS) were examined to determine their relationship with renal function.
The CAD score was associated with CAD (odds ratio with 95% confidence interval, 2.2 [1.3–5.2]; P = 0.0016) and remained significant when adjusted individually for age, albumin excretion rate (AER), blood pressure, waist circumference, intraabdominal fat, glycosylated hemoglobin, and lipids. DNS and RDS were significantly correlated with AER, cystatin C, and serum creatinine. The biomarker panels for diabetes were both significantly associated with T1D status (P < 0.05 for both).
We validated a urinary proteome pattern associated with CAD and urinary proteome patterns associated with T1D and DN.
PMCID: PMC2939844  PMID: 19132849
6.  Methodological Issues in Design and Analysis of a Matched Case-Control Study of a Vaccine’s Effectiveness 
Journal of clinical epidemiology  2007;60(11):1127-1131.
Case-control studies of the effectiveness of a vaccine are useful to answer important questions, such as the effectiveness of a vaccine over time, that usually are not addressed by pre-licensure clinical trials of the vaccine’s efficacy. This report describes methodological issues related to design and analysis that were used to determine the effects of time since vaccination and age at the time of vaccination.
Study Design and Setting
A matched case-control study of the effectiveness of varicella vaccine.
Sampling procedures and conditional logistic regression models including interaction terms are described.
Use of these methods will allow investigators to assess the effects of a wide range of variables, such as time since vaccination and age at the time of vaccination, on the effectiveness of a vaccine.
PMCID: PMC2096633  PMID: 17938054
case-control study; vaccines; statistical methods; sampling
7.  Parental Influence on Child Change in Physical Activity during a Family-Based Intervention for Child Weight Gain Prevention 
This study examined the association between parent and child change in physical activity during a family-based intervention for child weight gain prevention.
Daily step counts were recorded for parents and children in 83 families given a goal to increase activity by 2000 steps per day above baseline. Linear mixed effects models were utilized to predict child change in daily step counts from parental change in step counts.
Both maternal (p < .0001) and paternal (p < .0001) change in step counts for the current day strongly predicted child change in step counts for that day. On average, a child took an additional 2117.6 steps above baseline on days his or her mother met her goal versus 1175.2 additional steps when the mother did not meet her goal. The respective values were 1598.0 versus 1123.1 steps for fathers. Day of week moderated the maternal effect (p = 0.0019), with a larger impact on Saturday and Sunday compared to weekdays. A similar but non-significant pattern was observed for fathers.
Encouraging parents to increase physical activity, particularly on weekends, may be a highly effective way to leverage parental involvement in interventions to increase children's physical activity.
PMCID: PMC3624075  PMID: 21946342
pediatric overweight; parent-child associations; daily step counts
8.  Relationship Between Cystatin C and Coronary Artery Atherosclerosis Progression Differs by Type 1 Diabetes 
Cystatin C has been proposed to better estimate renal function and predict cardiovascular disease (CVD) than serum creatinine. To expand on our previous report, we investigated whether the relationship of cystatin C to progression of coronary artery atherosclerosis (CA) differed between individuals with type 1 diabetes (T1D) and persons without diabetes.
Coronary artery calcium was measured twice over 2.4 ± 0.4 years (n = 1,123, age = 39 ± 9 years, 47% male, 45% T1D). Significant CA progression was defined as a ≥2.5 increase in square root calcium volume score or development of clinical coronary artery disease. Stepwise multiple logistic regression was performed to investigate whether the association of cystatin C to CA progression differed by T1D status.
The main finding and novelty of this article is that while the univariate association of cystatin C to CA progression was similar in T1D patients and persons without diabetes mellitus and in the expected direction (increased cystatin C as a biomarker of worsening renal function associated with CA progression), the association of cystatin C to progression of CA differed by T1D status (P = 0.01) after adjustment for other CVD risk factors. Unexpectedly, in persons without diabetes mellitus having relatively normal renal function, increased cystatin C was associated with decreased CA progression (odd ratio [OR] = 0.65, 95% confidence interval 0.44–0.96, P = 0.029) after adjustment, primarily due to adjustment for body mass index (BMI). Removal of BMI from this model resulted in a 49% change in the OR.
Our hypothesis-generating data suggest a complex relationship among cystatin C, BMI, and CA progression that requires further study.
PMCID: PMC2883530  PMID: 20082582

Results 1-8 (8)