Dong D. Wang

Trends in Dietary Quality Among Adults in the United States, 1999 Through 2010

IMPORTANCE Many changes in the economy, policies related to nutrition, and food processing have occurred within the United States since 2000, and the net effect on dietary quality is not clear. These changes may have affected various socioeconomic groups differentially. OBJECTIVE To investigate trends in dietary quality from 1999 to 2010 in the US adult population and within socioeconomic subgroups. DESIGN, SETTING, AND PARTICIPANTS Nationally representative sample of 29 124 adults aged 20 to 85 years from the US 1999 to 2010 National Health and Nutrition Examination Survey. MAIN OUTCOMES AND MEASURES The Alternate Healthy Eating Index 2010 (AHEI-2010), an 11-dimension score (range, 0-10 for each component score and 0-110 for the total score), was used to measure dietary quality. A higher AHEI-2010 score indicated a more healthful diet. RESULTS The energy-adjusted mean of the AHEI-2010 increased from 39.9 in 1999 to 2000 to 46.8 in 2009 to 2010 (linear trend P < .001). Reduction in trans fat intake accounted for more than half of this improvement. The AHEI-2010 component score increased by 0.9 points for sugar-sweetened beverages and fruit juice (reflecting decreased consumption), 0.7 points for whole fruit, 0.5 points for whole grains, 0.5 points for polyunsaturated fatty acids, and 0.4 points for nuts and legumes over the 12-year period (all linear trend P < .001). Family income and education level were positively associated with total AHEI-2010, and the gap between low and high socioeconomic status widened over time, from 3.9 points in 1999 to 2000 to 7.8 points in 2009 to 2010 (interaction P = .01). CONCLUSIONS AND RELEVANCE Although a steady improvement in AHEI-2010 was observed across the 12-year period, the overall dietary quality remains poor. Better dietary quality was associated with higher socioeconomic status, and the gap widened with time. Future efforts to improve nutrition should address these disparities.

Exposure to the Chinese Famine in Early Life and the Risk of Metabolic Syndrome in Adulthood

OBJECTIVE To examine whether exposure to the Chinese famine during fetal life and early childhood is associated with the risks of metabolic syndrome and whether this association is modified by later life environment. RESEARCH DESIGN AND METHODS We used data of 7,874 adults born between 1954 and 1964 from the 2002 China National Nutrition and Health Survey. Famine exposure groups were defined as nonexposed; fetal exposed; and early childhood, midchildhood, or late childhood exposed. Excess death rate was used to determine the severity of the famine. The ATP III criteria were used for the definition of metabolic syndrome (three or more of the following variables: elevated fasting triglyceride levels, lower HDL cholesterol levels, elevated fasting glucose levels, higher waist circumference, high blood pressure). RESULTS In severely affected famine areas, adults who were exposed to the famine during fetal life had a higher risk of metabolic syndrome, as compared with nonexposed subjects (odds ratio 3.13 [95% CI 1.24–7.89, P = 0.016]). Similar associations were observed among adults who were exposed to the famine during early childhood, but not for adults exposed to the famine during mid- or late childhood. Participants who were born in severely affected famine areas and had Western dietary habits in adulthood or were overweight in adulthood had a particularly high risk of metabolic syndrome in later life. CONCLUSIONS Exposure to the Chinese famine during fetal life or infancy is associated with an increased risk of metabolic syndrome in adulthood. These associations are stronger among subjects with a Western dietary pattern or who were overweight in adulthood.

Adherence to healthy lifestyle and risk of gestational diabetes mellitus: prospective cohort study

Objective To quantify the association between a combination of healthy lifestyle factors before pregnancy (healthy body weight, healthy diet, regular exercise, and not smoking) and the risk of gestational diabetes. Design Prospective cohort study. Setting Nurses’ Health Study II, United States. Participants 20 136 singleton live births in 14 437 women without chronic disease. Main outcome measure Self reported incident gestational diabetes diagnosed by a physician, validated by medical records in a previous study. Results Incident first time gestational diabetes was reported in 823 pregnancies. Each lifestyle factor measured was independently and significantly associated with risk of gestational diabetes. The combination of three low risk factors (non-smoker, ≥150 minutes a week of moderate to vigorous physical activity, and healthy eating (top two fifths of Alternate Healthy Eating Index-2010 adherence score)) was associated with a 41% lower risk of gestational diabetes compared with all other pregnancies (relative risk 0.59, 95% confidence interval 0.48 to 0.71). Addition of body mass index (BMI) <25 before pregnancy (giving a combination of four low risk factors) was associated with a 52% lower risk of gestational diabetes compared with all other pregnancies (relative risk 0.48, 0.38 to 0.61). Compared with pregnancies in women who did not meet any of the low risk lifestyle factors, those meeting all four criteria had an 83% lower risk of gestational diabetes (relative risk 0.17, 0.12 to 0.25). The population attributable risk percentage of the four risk factors in combination (smoking, inactivity, overweight, and poor diet) was 47.5% (95% confidence interval 35.6% to 56.6%). A similar population attributable risk percentage (49.2%) was observed when the distributions of the four low risk factors from the US National Health and Nutrition Examination Survey (2007-10) data were applied to the calculation. Conclusions Adherence to a low risk lifestyle before pregnancy is associated with a low risk of gestational diabetes and could be an effective strategy for the prevention of gestational diabetes.

Report on childhood obesity in China (8): effects and sustainability of physical activity intervention on body composition of Chinese youth.

OBJECTIVES To determine whether a large-scale physical activity intervention could affect body composition in primary school students in Beijing, China. METHODS The study design was one-year cluster randomized controlled trial of physical activity intervention (20 min of daily exercise in the classroom) with an additional year of follow-up among 4 700 students aged 8-11 years at baseline. RESULTS After the one-year intervention, BMI increased by 0.56 kg/m(2) (SD 1.15) in the intervention group and by 0.72 kg/m(2) (SD 1.20) in the control group, with a mean difference of -0.15 kg/m(2) (95% CI: -0.28 to -0.02). BMI z score decreased by -0.05 (SD 0.44) in the intervention group, but increased by 0.01 (SD 0.46) in the control group, with a mean difference of -0.07 (-0.13 to -0.01). After another year of follow up, compared to the control group, children in the intervention group had significantly lower BMI (-0.13, -0.25 to -0.01), BMI z score (-0.05, -0.10 to -0.01), fat mass (-0.27 kg, -0.53 to -0.02) and percent body fat (-0.53, -1.00 to -0.05). The intervention had a more pronounced effect on weight, height, BMI, BMI z score, and body composition among obese children than among normal weight or overweight children. Compared to the control group, the intervention group had a significantly higher percentage of children who maintained or reduced their BMI z score at year 1 (P=0.008) and year 2 (P=0.04). CONCLUSIONS These findings suggest that 20 min of daily moderate to vigorous physical activity during the school year is a feasible and effective way to prevent excessive gain of body weight, BMI, and body fatness in primary school students.

Dietary Patterns Are Associated with Stroke in Chinese Adults

We recently featured Chinese dietary patterns that were associated with obesity, hyperglycemia, hypertension, and metabolic syndrome. In this study, we examined the association of those dietary patterns and risk of stroke among 26,276 Chinese adults aged ≥45 y by using data from the 2002 China National Nutrition and Health Survey and explored whether those associations were mediated by obesity, hypertension, hyperglycemia, and other cardiovascular risk factors. The traditional southern Chinese dietary pattern, characterized by high intakes of rice and vegetables and moderate intakes in animal foods, was related to the lowest prevalence of stroke. Compared to the traditional southern dietary pattern, the traditional northern Chinese dietary pattern, characterized by high intakes of refined cereal products, potatoes, and salted vegetables, was associated with an elevated risk of stroke [OR = 1.96 (95% CI = 1.48-2.60); P < 0.0001]. Adjustment for conventional cardiovascular risk factors did not appreciably change the association [multivariate adjusted OR = 1.59 (95%CI = 1.16-2.17); P = 0.004]. The Western dietary pattern characterized by high consumption of beef, fruit, eggs, poultry, and seafood is also associated with an elevated risk of stroke [OR = 2.36 (95%CI = 1.82-3.06); P < 0.0001], but the associations became nonsignificant after adjustment for obesity, hypertension, hyperglycemia, and dyslipidemia. In conclusion, we found that the traditional southern dietary pattern was related to low prevalence of stroke and the traditional northern dietary pattern was associated with an increased stroke risk. The Western dietary patterns also association with high risk of stroke, which was largely mediated by obesity, hypertension, hyperglycemia, and dyslipidemia.

Improvements In US Diet Helped Reduce Disease Burden And Lower Premature Deaths, 1999–2012; Overall Diet Remains Poor

Evaluation of time trends in dietary quality and their relation to disease burden provides essential feedback for policy making. We used an index titled the Alternate Healthy Eating Index 2010 to evaluate trends in dietary quality among 33,885 US adults. From 1999 to 2012 the index increased from 39.9 to 48.2 (perfect score = 110). Gaps in performance on the index across socioeconomic groups persisted or widened. Using data relating index scores to health outcomes in two large cohorts, we estimated that the improvements in dietary quality from 1999 to 2012 prevented 1.1 million premature deaths. Also, this improvement in diet quality resulted in 8.6 percent fewer cardiovascular disease cases, 1.3 percent fewer cancer cases, and 12.6 percent fewer type 2 diabetes cases. Although the steady improvement in dietary quality likely accounted for substantial reductions in disease burden from 1999 to 2012, overall dietary quality in the United States remains poor. Policy initiatives are needed to ensure further improvements.

Ethnic differences in body composition and obesity related risk factors: study in Chinese and white males living in China.

The purpose of this cross-sectional observational study was to identify ethnic differences in body composition and obesity-related risk factors between Chinese and white males living in China. 115 Chinese and 114 white male pilots aged 28–63 years were recruited. Fasting body weight, height and blood pressure were measured following standard procedures. Whole-body and segmental body composition were measured using an 8-contact electrode bioimpedance analysis (BIA) system. Fasting serum glucose, fasting plasma total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, and triglycerides (TG) were assessed using automatic biochemistry analyzer. After adjusting for age and body mass index (BMI), Chinese males had significantly higher percentage of body fat (PBF) both with respect to whole body (Chinese: 23.7%±0.2% vs. Whites: 22.4%±0.2%) and the trunk area (Chinese: 25.0%±0.3% vs. Whites: 23.2%±0.3%) compared to their white counterparts. At all BMIs, Chinese males had significantly higher fasting glucose levels (Chinese: 5.7±1.0 mmol/L vs. Whites: 5.2±1.0 mmol/L) but lower high-density lipoprotein levels (Chinese: 0.8±1.0 mmol/L vs. Whites: 1.0±1.0 mmol/L) than white males. In addition, a marginally significantly higher diastolic blood pressure was found among Chinese men than that among white men (Chinese: 80±1.0 mmHg vs. Whites: 77±1.0 mmHg). Chinese males had more body fat and a greater degree of central fat deposition pattern than that seen in white males in the present study. Furthermore, data on blood pressure, fasting glucose and blood lipids suggest that Chinese men may be more prone to obesity-related risk factors than white men.

Plasma Ceramides, Mediterranean Diet, and Incident Cardiovascular Disease in the Predimed Trial

Background: Although in vitro studies and investigations in animal models and small clinical populations have suggested that ceramides may represent an intermediate link between overnutrition and certain pathological mechanisms underlying cardiovascular disease (CVD), no prospective studies have investigated the association between plasma ceramides and risk of CVD. Methods: The study population consisted of 980 participants from the PREDIMED trial (Prevención con Dieta Mediterránea), including 230 incident cases of CVD and 787 randomly selected participants at baseline (including 37 overlapping cases) followed for ⩽7.4 years. Participants were randomized to a Mediterranean diet supplemented with extra virgin olive oil, a Mediterranean diet supplemented with nuts, or a control diet. Plasma ceramide concentrations were measured on a liquid chromatography tandem mass spectrometry metabolomics platform. The primary outcome was a composite of nonfatal acute myocardial infarction, nonfatal stroke, or cardiovascular death. Hazard ratios were estimated with weighted Cox regression models using Barlow weights to account for the case-cohort design. Results: The multivariable hazard ratios (HR) and 95% confidence intervals (CIs) comparing the extreme quartiles of plasma concentrations of C16:0, C22:0, C24:0, and C24:1 ceramides were 2.39 (1.49–3.83, Ptrend<0.001), 1.91 (1.21–3.01, Ptrend=0.003), 1.97 (1.21–3.20, Ptrend=0.004), and 1.73 (1.09–2.74, Ptrend=0.011), respectively. The ceramide score, calculated as a weighted sum of concentrations of four ceramides, was associated with a 2.18-fold higher risk of CVD across extreme quartiles (HR, 2.18; 95% CI, 1.36–3.49; Ptrend<0.001). The association between baseline ceramide score and incident CVD varied significantly by treatment groups (Pinteraction=0.010). Participants with a higher ceramide score and assigned to either of the 2 active intervention arms of the trial showed similar CVD risk to those with a lower ceramide score, whereas participants with a higher ceramide score and assigned to the control arm presented significantly higher CVD risk. Changes in ceramide concentration were not significantly different between Mediterranean diet and control groups during the first year of follow-up. Conclusions: Our study documented a novel positive association between baseline plasma ceramide concentrations and incident CVD. In addition, a Mediterranean dietary intervention may mitigate potential deleterious effects of elevated plasma ceramide concentrations on CVD. Clinical Trial Registration: URL: http://www.isrctn.com. Unique identifier: ISRCTN35739639.

Increases in Plasma Tryptophan Are Inversely Associated with Incident Cardiovascular Disease in the Prevención con Dieta Mediterránea (PREDIMED) Study

Background: During development of cardiovascular disease (CVD), interferon-γ-mediated inflammation accelerates degradation of tryptophan into downstream metabolites. A Mediterranean diet (MedDiet) consisting of a high intake of extra-virgin olive oil (EVOO), nuts, fruits, vegetables, and cereals has been demonstrated to lower the risk of CVD. The longitudinal relation between tryptophan and its downstream metabolites and CVD in the context of a MedDiet is unstudied.Objective: We sought to investigate the relation between metabolites in the tryptophan-kynurenine pathway and CVD in the context of a MedDiet pattern.Methods: We used a case-cohort design nested in the Prevención con Dieta Mediterránea randomized controlled trial. There were 231 CVD cases (stroke, myocardial infarction, cardiovascular death) among 985 participants over a median of 4.7 y of follow-up [mean ± SD age: 67.6 ± 6.1 y; 53.7% women; mean ± SD body mass index (in kg/m2): 29.7 ± 3.7]. We assessed plasma tryptophan, kynurenine, kynurenic acid, 3-hydroxyanthranilic acid, and quinolinic acid concentrations at baseline and after 1 y of intervention with a MedDiet. We combined these metabolites in a kynurenine risk score (KRS) by weighting each metabolite by the adjusted coefficient of its associations with CVD. Cox models were used in the primary analysis.Results: Increases in tryptophan after 1 y were associated with a lower risk of composite CVD (HR per SD: 0.79; 95% CI: 0.63, 0.98). The baseline kynurenic acid concentration was associated with a higher risk of myocardial infarction and coronary artery disease death but not stroke. A higher KRS was more strongly associated with CVD in the control group than in the 2 intervention groups (P-interaction = 0.003). Adjustment for changes in plasma tryptophan attenuated the inverse association between MedDiet+EVOO and CVD.Conclusions: An increase in the plasma tryptophan concentration was significantly associated with a decreased risk of CVD. A MedDiet may counteract the deleterious effects of a high kynurenine risk score.

Prevalence and Correlates of Diabetic Peripheral Neuropathy in a Saudi Arabic Population: A Cross-Sectional Study

The purpose of this cross-sectional study was to investigate the prevalence and correlates of diabetic peripheral neuropathy (DPN) in a Saudi population. The study population consisted of 552 diabetic participants with an average age of 53.4 years. Among this population, 62.7% were male and 94.9% had type 2 diabetes. The average body mass index was 31.1 kg/m2. DPN was diagnosed based on a combination of reduced vibration perception measured by neurothesiometer and/or reduced light touch perception evaluated by the 10-g Semmes-Weinstein monofilament, as well as neurological symptoms. Information on socio-demographic variables, smoking status, duration of diabetes, and medications was obtained through interviews by physicians. Body weight, height, waist circumference, blood pressure and clinical markers were assessed following standard procedures. The prevalence of DPN in this population was 19.9% (95% CI, 16.7%-23.5%). In the multivariable analyses, longer duration of diabetes [odds ratio (OR) for every 5-year increase, 2.49, 95% CI, 1.75-3.53], abdominal obesity (OR, 2.53, 95% CI, 1.41-4.55), and higher levels of fasting blood glucose (OR for every 1 mmol/L increase, 1.05, 95% CI, 0.99-1.12), creatinine (OR for every 10 µmol/L increase, 1.07, 95% CI, 0.99-1.14) and white blood cell count (OR for every 106/L increase, 1.08, 95% CI, 1.01-1.16) were associated with higher odds of DPN, while oral hypoglycemic medication use was associated with a lower odds of DPN (OR, 0.47, 95% CI, 0.26-0.85). In this large Saudi population, several correlates for DPN, in addition to glycemic control and diabetes duration, were identified, including abdominal obesity, creatinine and white blood cell count.