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Biomedical subjects

David S Ludwig

Publications and source records attributed to David S Ludwig.

At least 19 recordsLinked to original sources
PubMed2007

Relationship between funding source and conclusion among nutrition-related scientific articles.

BACKGROUND: Industrial support of biomedical research may bias scientific conclusions, as demonstrated by recent analyses of pharmaceutical studies. However, this issue has not been systematically examined in the area of nutrition research. The purpose of this study is to characterize financial sponsorship of scientific articles addressing the health effects of three commonly consumed beverages, and to determine how sponsorship affects published conclusions. METHODS AND FINDINGS: Medline searches of worldwide literature were used to identify three article types (interventional studies, observational studies, and scientific reviews) about soft drinks, juice, and milk published between 1 January, 1999 and 31 December, 2003. Financial sponsorship and article conclusions were classified by independent groups of coinvestigators. The relationship between sponsorship and conclusions was explored by exact tests and regression analyses, controlling for covariates. 206 articles were included in the study, of which 111 declared financial sponsorship. Of these, 22% had all industry funding, 47% had no industry funding, and 32% had mixed funding. Funding source was significantly related to conclusions when considering all article types (p = 0.037). For interventional studies, the proportion with unfavorable conclusions was 0% for all industry funding versus 37% for no industry funding (p = 0.009). The odds ratio of a favorable versus unfavorable conclusion was 7.61 (95% confidence interval 1.27 to 45.73), comparing articles with all industry funding to no industry funding. CONCLUSIONS: Industry funding of nutrition-related scientific articles may bias conclusions in favor of sponsors' products, with potentially significant implications for public health.

Animals↗
PubMed2006

Inflammation and changes in metabolic syndrome abnormalities in US adolescents: findings from the 1988-1994 and 1999-2000 National Health and Nutrition Examination Surveys.

BACKGROUND: Understanding of C-reactive protein (CRP) in adult metabolic syndrome is increasing; however, this relationship in children is less clear. METHODS: We compared the prevalence of metabolic abnormalities and metabolic syndrome in fasting 12- to 19-year-olds from the 1999-2000 and 1988-1994 National Health and Nutrition Examination Survey (NHANES). In the more recent dataset we explored the relationship between metabolic abnormalities and CRP as measured by a high-sensitivity assay. RESULTS: The prevalence of central obesity, low HDL-cholesterol, and hypertension increased between the 2 surveys. Three or more abnormalities (metabolic syndrome) were found in 12.7% [95% confidence interval (CI), 10.0%-15.4%] of fasting adolescents from the 1999-2000 survey, compared with 9.2% (95% CI, 7.8%-10.6%; P < 0.001) in the 1988-1994 dataset, with increases also seen in sex and ethnic/racial subgroups. Increases in metabolic syndrome were primarily attributable to increasing body mass index (BMI); prevalence of BMI at or above the 85th percentile increased from 25.9% to 30.5%. Metabolic syndrome was much more prevalent in overweight compared with normal-weight adolescents (38.6% vs 1.4%; P < 0.001). Median CRP increased with increasing numbers of metabolic abnormalities and was higher in adolescents with metabolic syndrome than in those without. CRP was higher in adolescents with BMI at or above the 85th percentile than those with normal BMI. CONCLUSIONS: Metabolic abnormalities and the metabolic syndrome phenotype are increasingly prevalent in US adolescents, attributable in part to the increasing incidence of overweight. Adolescents with more metabolic abnormalities have higher CRP, which may be an indicator of greater metabolic derangement and future cardiovascular risk.

Adolescent↗
PubMed2006

When children eat what they watch: impact of television viewing on dietary intake in youth.

OBJECTIVES: To test whether increased television viewing is associated with increased total energy intake and with increased consumption of foods commonly advertised on television, and to test whether increased consumption of these foods mediates the relationship between television viewing and total energy intake. DESIGN: Prospective observational study with baseline (fall 1995) and follow-up (spring 1997) measures of youth diet, physical activity, and television viewing. We used food advertising data to identify 6 food groups for study (sweet baked snacks, candy, fried potatoes, main courses commonly served as fast food, salty snacks, and sugar-sweetened beverages). SETTING AND PARTICIPANTS: Five public schools in 4 communities near Boston. The sample included 548 students (mean age at baseline, 11.70 years; 48.4% female; and 63.5% white). MAIN OUTCOME MEASURES: Change in total energy intake and intake of foods commonly advertised on television from baseline to follow-up. RESULTS: After adjusting for baseline covariates, each hour increase in television viewing was associated with an additional 167 kcal/d (95% confidence interval, 136-198 kcal/d; P<.001) and with increases in the consumption of foods commonly advertised on television. Including changes in intakes of these foods in regression models provided evidence of their mediating role, diminishing or rendering nonsignificant the associations between change in television viewing and change in total energy intake. CONCLUSIONS: Increases in television viewing are associated with increased calorie intake among youth. This association is mediated by increasing consumption of calorie-dense low-nutrient foods frequently advertised on television.

Advertising↗
PubMed2006

Effects of decreasing sugar-sweetened beverage consumption on body weight in adolescents: a randomized, controlled pilot study.

OBJECTIVE: The role of sugar-sweetened beverages (SSBs) in promoting obesity is controversial. Observational data link SSB consumption with excessive weight gain; however, randomized, controlled trials are lacking and necessary to resolve the debate. We conducted a pilot study to examine the effect of decreasing SSB consumption on body weight. METHODS: We randomly assigned 103 adolescents aged 13 to 18 years who regularly consumed SSBs to intervention and control groups. The intervention, 25 weeks in duration, relied largely on home deliveries of noncaloric beverages to displace SSBs and thereby decrease consumption. Change in SSB consumption was the main process measure, and change in body mass index (BMI) was the primary end point. RESULTS: All of the randomly assigned subjects completed the study. Consumption of SSBs decreased by 82% in the intervention group and did not change in the control group. Change in BMI, adjusted for gender and age, was 0.07 +/- 0.14 kg/m2 (mean +/- SE) for the intervention group and 0.21 +/- 0.15 kg/m2 for the control group. The net difference, -0.14 +/- 0.21 kg/m2, was not significant overall. However, baseline BMI was a significant effect modifier. Among the subjects in the upper baseline-BMI tertile, BMI change differed significantly between the intervention (-0.63 +/- 0.23 kg/m2) and control (+0.12 +/- 0.26 kg/m2) groups, a net effect of -0.75 +/- 0.34 kg/m2. The interaction between weight change and baseline BMI was not attributable to baseline consumption of SSBs. CONCLUSIONS: A simple environmental intervention almost completely eliminated SSB consumption in a diverse group of adolescents. The beneficial effect on body weight of reducing SSB consumption increased with increasing baseline body weight, offering additional support for American Academy of Pediatrics guidelines to limit SSB consumption.

Adolescent↗
PubMed2005

Misdirection on the road to Shangri-La.

Will life expectancy in the United States rise or fall in this century? The implications of either scenario are far reaching. We contend that the rise of childhood obesity in the United States in the past three decades has been so dramatic that it will soon lead to higher than expected death rates at middle ages and a possible decline in life expectancy by midcentury. The most detrimental health and longevity effects will not be seen for decades--a phenomenon that cannot be detected by current methods used to forecast life expectancy or estimate the number of deaths currently attributable to obesity. This scenario contrasts sharply with the views of mathematical demographers who generate forecasts by relying on the assumption that the U.S. pattern of longevity will follow that of other longer lived nations and on the extrapolation of historical trends in life expectancy into the future.

Journal Article↗
PubMed2005

Misdirection on the road to Shangri-La.

Will life expectancy in the United States rise or fall in this century? The implications of either scenario are far reaching. We contend that the rise of childhood obesity in the United States in the past three decades has been so dramatic that it will soon lead to higher than expected death rates at middle ages and a possible decline in life expectancy by midcentury. The most detrimental health and longevity effects will not be seen for decades--a phenomenon that cannot be detected by current methods used to forecast life expectancy or estimate the number of deaths currently attributable to obesity. This scenario contrasts sharply with the views of mathematical demographers who generate forecasts by relying on the assumption that the U.S. pattern of longevity will follow that of other longer lived nations and on the extrapolation of historical trends in life expectancy into the future.

Adolescent↗
PubMed2005

A potential decline in life expectancy in the United States in the 21st century.

Forecasts of life expectancy are an important component of public policy that influence age-based entitlement programs such as Social Security and Medicare. Although the Social Security Administration recently raised its estimates of how long Americans are going to live in the 21st century, current trends in obesity in the United States suggest that these estimates may not be accurate. From our analysis of the effect of obesity on longevity, we conclude that the steady rise in life expectancy during the past two centuries may soon come to an end.

Aged↗
PubMed2005

Best practice guidelines in pediatric/adolescent weight loss surgery.

OBJECTIVE: To establish evidence-based guidelines for best practices in pediatric/adolescent weight loss surgery (WLS). RESEARCH METHODS AND PROCEDURES: We carried out a systematic search of English-language literature in MEDLINE on WLS performed on children and adolescents. Key words were used to narrow the field for a selective review of abstracts. Data were extracted, and evidence categories were assigned according to a grading system based on established evidence-based models. Eight pertinent case series, published between 1980 and 2004, were identified and reviewed. These data were supplemented with expert opinions and literature on WLS in adults. RESULTS: Recommendations focused on patient safety, reduction of medical errors, systems improvements, credentialing, and future research. We developed evidence-based criteria for eligibility, assessment, treatment, and follow-up; recommended surgical procedures based on the best available evidence; and established minimum guideline requirements for data collection. DISCUSSION: Lack of adequate data and gaps in knowledge were cited as important reasons for caution. Physiological status, comprehensive screening of patients and their families, and required education and counseling were identified as key factors in assessing eligibility for surgery. Data collection and peer review were also identified as important issues in the delivery of best practice care.

Adolescent↗
PubMed2005

Effects of an ad libitum low-glycemic load diet on cardiovascular disease risk factors in obese young adults.

BACKGROUND: The optimal nutritional approach for the prevention of cardiovascular disease among obese persons remains a topic of intense controversy. Available approaches range from conventional low-fat to very-low-carbohydrate diets. OBJECTIVE: The aim of this pilot study was to evaluate the efficacy of an ad libitum low-glycemic load diet, without strict limitation on carbohydrate intake, as an alternative to a conventional low-fat diet. DESIGN: A randomized controlled trial compared 2 dietary treatments in obese young adults (n = 23) over 12 mo. The experimental treatment emphasized ad libitum consumption of low-glycemic-index foods, with 45-50% of energy from carbohydrates and 30-35% from fat. The conventional treatment was restricted in energy (250-500 kcal/d deficit) and fat (<30% of energy), with 55-60% of energy from carbohydrate. We compared changes in study outcomes by repeated-measures analysis of log-transformed data and expressed the results as mean percentage change. RESULTS: Body weight decreased significantly over a 6-mo intensive intervention in both the experimental and conventional diet groups (-8.4% and -7.8%, respectively) and remained below baseline at 12 mo (-7.8% and -6.1%, respectively). The experimental diet group showed a significantly greater mean decline in plasma triacylglycerols than did the conventional diet group (-37.2% and -19.1%, respectively; P = 0.005). Mean plasminogen activator inhibitor 1 concentrations decreased (-39.0%) in the experimental diet group but increased (33.1%) in the conventional diet group (P = 0.004). Changes in cholesterol concentrations, blood pressure, and insulin sensitivity did not differ significantly between the groups. CONCLUSION: An ad libitum low-glycemic load diet may be more efficacious than a conventional, energy-restricted, low-fat diet in reducing cardiovascular disease risk.

Adult↗
PubMed2005

Association of consumption of fried food away from home with body mass index and diet quality in older children and adolescents.

OBJECTIVES: Rates of overweight have increased dramatically among children in the United States. Although an increase in consumption of food prepared away from home has paralleled overweight trends, few data exist relating food prepared away from home to change in BMI in children. The goals of this study were to (1) examine the cross-sectional and longitudinal associations between consumption of fried foods away from home (FFA) and BMI and (2) examine the cross-sectional associations between intake of FFA and several measures of diet quality. METHODS: We studied a cohort of 7745 girls and 6610 boys, aged 9 to 14 years, at baseline in 1996. We obtained BMI from self-reported height and weight, measures of diet quality from a food frequency questionnaire, and weekly servings of FFA during the previous year. We performed linear regression analyses to assess the longitudinal associations between change in consumption of FFA on change in BMI, using data from three 1-year periods from 1996 through 1999. We also related consumption of FFA with intake of selected foods and nutrients at baseline. RESULTS: In cross-sectional analyses, adjusting for potential confounders, mean (SE) BMI was 19.1 (0.13) among children who ate FFA "never or <1/week," 19.2 (0.13) among those who responded "1 to 3 times/week," and 19.3 (0.18) among those who responded "4 to 7 times/week." In longitudinal multivariate models, increasing (over 1 year) consumption of FFA "never or <1/week" to "4 to 7/week" was associated with increasing BMI (beta = 0.21 kg/m2; 95% confidence interval: 0.03-0.39) compared with those with low consumption of FFA at baseline and 1 year later. At baseline, frequency of eating FFA was associated with greater intakes of total energy, sugar-sweetened beverages, and trans fat, as well as lower consumption of low-fat dairy foods and fruits and vegetables. CONCLUSIONS: These data suggest that older children who consume greater quantities of FFA are heavier, have greater total energy intakes, and have poorer diet quality. Furthermore, increasing consumption of FFA over time may lead to excess weight gain.

Adolescent↗
PubMed2005

Effect of low-dose insulin treatment on body weight and physical development in children and adolescents at risk for type 1 diabetes.

OBJECTIVE: Insulin's role in body weight regulation is controversial. We evaluated the effect of parenteral insulin on body weight and physical development in children and adolescents at risk for type 1 diabetes. RESEARCH DESIGN AND METHODS: We performed a secondary analysis of the parenteral arm of the Diabetes Prevention Trial-Type 1 Diabetes (DPT-1), a randomized controlled trial of low-dose parenteral insulin (human ultralente insulin at 0.25 units x kg(-1) x day(-1)) in subjects with a >50% 5-year risk of diabetes. Analysis was limited to 100 subjects (55 intervention, 45 closely monitored) aged <19 years at randomization whose weight was followed for at least 2 years by study end after excluding subjects who were noncompliant within 2 years or developed diabetes within 36 months of randomization. RESULTS: Subjects ranged in age from 4.07 to 18.98 years. There were no significant differences at randomization between subjects in each group with respect to sex, age, weight, height, BMI, Tanner stage, or glucose tolerance. We found no differences over 2 years between the intervention and closely monitored groups in the change in weight (median 6.8 vs. 6.0 kg, P = 0.65), height (median 10.7 vs. 10.1 cm, P = 0.66), BMI (median 0.9 vs. 1.0 kg/m2, P = 0.79), or Tanner stage (median 0 vs. 0, P = 0.35). Multiple regression showed no effect of insulin on change in weight (P = 0.53) or BMI (P = 0.95) over 2 years after adjustment for relevant covariates. CONCLUSIONS: Low-dose insulin treatment for 2 years did not affect the weight, BMI, or physical development of nondiabetic children and adolescents.

Adolescent↗
PubMed2004

Effects of a low-glycemic load diet on resting energy expenditure and heart disease risk factors during weight loss.

CONTEXT: Weight loss elicits physiological adaptations relating to energy intake and expenditure that antagonize ongoing weight loss. OBJECTIVE: To test whether dietary composition affects the physiological adaptations to weight loss, as assessed by resting energy expenditure. DESIGN, STUDY, AND PARTICIPANTS: A randomized parallel-design study of 39 overweight or obese young adults aged 18 to 40 years who received an energy-restricted diet, either low-glycemic load or low-fat. Participants were studied in the General Clinical Research Centers of the Brigham and Women's Hospital and the Children's Hospital, Boston, Mass, before and after 10% weight loss. The study was conducted from January 4, 2001, to May 6, 2003. MAIN OUTCOME MEASURES: Resting energy expenditure measured in the fasting state by indirect calorimetry, body composition by dual-energy x-ray absorptiometry, cardiovascular disease risk factors, and self-reported hunger. RESULTS: Resting energy expenditure decreased less with the low-glycemic load diet than with the low-fat diet, expressed in absolute terms (mean [SE], 96 [24] vs 176 [27] kcal/d; P = .04) or as a proportion (5.9% [1.5%] vs 10.6% [1.7%]; P = .05). Participants receiving the low-glycemic load diet reported less hunger than those receiving the low-fat diet (P = .04). Insulin resistance (P = .01), serum triglycerides (P = .01), C-reactive protein (P = .03), and blood pressure (P = .07 for both systolic and diastolic) improved more with the low-glycemic load diet. Changes in body composition (fat and lean mass) in both groups were very similar (P = .85 and P = .45, respectively). CONCLUSIONS: Changes in dietary composition within prevailing norms can affect physiological adaptations that defend body weight. Reduction in glycemic load may aid in the prevention or treatment of obesity, cardiovascular disease, and diabetes mellitus.

Adult↗
PubMed2004

Prevalence of the metabolic syndrome in American adolescents: findings from the Third National Health and Nutrition Examination Survey.

BACKGROUND: Metabolic syndrome (MetS) is defined by the Third Report of the Adult Treatment Panel (ATP III) using criteria easily applied by clinicians and researchers. There is no standard pediatric definition. METHODS AND RESULTS: We defined pediatric MetS using criteria analogous to ATP III as > or =3 of the following: (1) fasting triglycerides > or =1.1 mmol/L (100 mg/dL); (2) HDL <1.3 mmol/L (50 mg/dL), except in boys aged 15 to 19 years, in whom the cutpoint was <1.2 mmol/L (45 mg/dL); (3) fasting glucose > or =6.1 mmol/L (110 mg/dL); (4) waist circumference >75th percentile for age and gender; and (5) systolic blood pressure >90th percentile for gender, age, and height. MetS prevalence in US adolescents was estimated with the Third National Health and Nutritional Survey 1988 to 1994. Among 1960 children aged > or =12 years who fasted > or =8 hours, two thirds had at least 1 metabolic abnormality, and nearly 1 in 10 had MetS. The racial/ethnic distribution was similar to adults: Mexican-Americans, followed by non-Hispanic whites, had a greater prevalence of MetS compared with non-Hispanic blacks (12.9%, [95% CI 10.4% to 15.4%]; 10.9%, [95% CI 8.4% to 13.4%]; and 2.5%, [95% CI 1.3% to 3.7%], respectively). Nearly one third (31.2% [95% CI 28.3% to 34.1%]) of overweight/obese adolescents had MetS. CONCLUSIONS: Our definition of pediatric MetS, designed to be closely analogous to ATP III, found MetS is common in adolescents and has a similar racial/ethnic distribution to adults in this representative national sample. Because childhood MetS likely tracks into adulthood, early identification may help target interventions to improve future cardiovascular health.

Adolescent↗
PubMed2004

Sugar-sweetened beverages, weight gain, and incidence of type 2 diabetes in young and middle-aged women.

CONTEXT: Sugar-sweetened beverages like soft drinks and fruit punches contain large amounts of readily absorbable sugars and may contribute to weight gain and an increased risk of type 2 diabetes, but these relationships have been minimally addressed in adults. OBJECTIVE: To examine the association between consumption of sugar-sweetened beverages and weight change and risk of type 2 diabetes in women. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort analyses conducted from 1991 to 1999 among women in the Nurses' Health Study II. The diabetes analysis included 91,249 women free of diabetes and other major chronic diseases at baseline in 1991. The weight change analysis included 51,603 women for whom complete dietary information and body weight were ascertained in 1991, 1995, and 1999. We identified 741 incident cases of confirmed type 2 diabetes during 716,300 person-years of follow-up. MAIN OUTCOME MEASURES: Weight gain and incidence of type 2 diabetes. RESULTS: Those with stable consumption patterns had no difference in weight gain, but weight gain over a 4-year period was highest among women who increased their sugar-sweetened soft drink consumption from 1 or fewer drinks per week to 1 or more drinks per day (multivariate-adjusted means, 4.69 kg for 1991 to 1995 and 4.20 kg for 1995 to 1999) and was smallest among women who decreased their intake (1.34 and 0.15 kg for the 2 periods, respectively) after adjusting for lifestyle and dietary confounders. Increased consumption of fruit punch was also associated with greater weight gain compared with decreased consumption. After adjustment for potential confounders, women consuming 1 or more sugar-sweetened soft drinks per day had a relative risk [RR] of type 2 diabetes of 1.83 (95% confidence interval [CI], 1.42-2.36; P<.001 for trend) compared with those who consumed less than 1 of these beverages per month. Similarly, consumption of fruit punch was associated with increased diabetes risk (RR for > or =1 drink per day compared with <1 drink per month, 2.00; 95% CI, 1.33-3.03; P =.001). CONCLUSION: Higher consumption of sugar-sweetened beverages is associated with a greater magnitude of weight gain and an increased risk for development of type 2 diabetes in women, possibly by providing excessive calories and large amounts of rapidly absorbable sugars.

Adult↗