A comparison of two methods to ascertain dietary intake: the CARDIA Study

High Dietary Sodium, Measured Using Spot Urine Samples, is Associated with Higher Blood Pressure among Young Adults in Haiti

Background

Hypertension (HTN) is the leading cardiovascular disease (CVD) risk factor in Haiti and is likely driven by poverty-related social and dietary factors. Salt consumption in Haiti is hypothesized to be high but has never been rigorously quantified.

Methods

We used spot urine samples from a subset of participants in the population-based Haiti Cardiovascular Disease Cohort to estimate population mean daily sodium intake. We compared three previously validated formulas for estimating dietary sodium intake using urine sodium, urine creatinine, age, sex, height, and weight. We explored the association between dietary sodium intake and blood pressure, stratified by age group.

Results

A total of 1,240 participants had spot urine samples. Median age was 38 years (range 18-93), and 48% were female. The mean dietary sodium intake was 3.5-5.0 g/day across the three estimation methods, with 94.2%-97.9% of participants consuming above the World Health Organization (WHO) recommended maximum of 2 g/day of sodium. Among young adults aged 18-29, increasing salt intake from the lowest quartile of consumption (<3.73 g/day) to the highest quartile (>5.88 g/day) was associated with a mean 8.71 mmHg higher systolic blood pressure (SBP) (95% confidence interval: 3.35, 14.07; p = 0.001). An association was not seen in older age groups. Among participants under age 40, those with SBP ≥120 mmHg consumed 0.5 g/day more sodium than those with SBP <120 mmHg (95% confidence interval: 0.08, 0.69; p = 0.012).

Conclusions

Nine out of 10 Haitian adults in our study population consumed more than the WHO recommended maximum for daily sodium intake. In young adults, higher sodium consumption was associated with higher SBP. This represents an inflection point for increased HTN risk early in the life course and points to dietary salt intake as a potential modifiable risk factor for primordial and primary CVD prevention in young adults.

Lifestyle and weight predictors of a healthy overweight profile over a 20-year follow-up

OBJECTIVE

To examine whether changes in modifiable risk factors [physical activity, cardiorespiratory fitness (CRF), body weight, and diet composition] are associated with the transition to metabolically healthy overweight/obese (MHOW) versus metabolically abnormal overweight/obese.

METHODS

Analysis included 1,358 adults [aged 25.0 (3.5) years] from the CARDIA study who were healthy at baseline and had overweight/obesity at follow-up. Participants with zero or one of the following six risk factors were classified as MHOW: elevated triglycerides, LDL, blood pressure, fasting glucose, and HOMA-insulin resistance and low HDL.

RESULTS

Over the 20-year follow-up, the sample gained weight (BMI 24.5 to 31.1 kg/m(2) ), and the prevalence of MHOW was 47% at follow-up. After adjusting for changes in CRF, diet, and weight change, physical activity and macronutrient intake were not independently associated with MHOW (P > 0.05), while changes in CRF [fit-unfit: RR (95%) = 0.58, 0.52-0.66; unfit-unfit: RR = 0.67, 0.58-0.76, versus fit-fit] and weight [gain: RR (95%) = 0.54, 0.43-0.67; cycle: RR = 0.74, 0.57-0.94, versus stable] were independently associated with MHOW.

CONCLUSIONS

Focusing on high CRF and strategies to limit weight gain may be important for individuals with overweight and obesity in early to mid-adulthood to maintain a metabolically healthy profile.

PTGS1, PTGS2, ALOX5, ALOX12, ALOX15, and FLAP SNPs: interaction with fatty acids in colon cancer and rectal cancer

Dietary polyunsaturated fatty acids (PUFAs) can be converted to prostaglandins and leukotrienes. Oxygenation of omega-6 PUFAs generally results in the production of pro-inflammatory mediators, whereas oxygenated products of omega-3 (n-3) PUFAs generally have lower inflammatory activity. We hypothesize that elevated n-3 PUFA intakes from fish are associated with lower risk of colorectal cancer among those with genetic variants that result in higher levels of pro-inflammatory mediators. In population-based case-control studies of colon (case n = 1,574) and rectal cancer (case n = 791) and disease-free controls (n = 2,969), we investigated interactions between dietary fatty acid intake and 107 candidate polymorphisms and tagSNPs in PTGS1, PTGS2, ALOX12, ALOX5, ALOX15, and FLAP. The two studies used an identical genotyping protocol. We observed interactions and statistically significant increases in colon cancer risk for low docosahexaenoic acid intake among those with the PTGS1 rs10306110 (-1,053 A > G) variant genotypes (OR = 1.6, 95 % confidence interval = 1.1-2.3, adj. p = 0.06) and rectal cancer risk for low total fat intake among those with the variant PTGS1 rs10306122 (7,135 A > G) (OR(vs.wt) = 1.80, 1.02-2.99; adj. p = 0.08). The ALOX15 rs11568131 (10,339 C > T) wild type in combination with a high inflammation score (low EPA intake, high AA intake, no regular NSAID use, high BMI, smoking) was associated with increased colon cancer risk (OR = 2.28, 1.7-3.07). Rectal cancer risk was inversely associated with a low inflammation score among PTGS2 rs4648276 (3,934 T > C) variant allele carriers (OR = 0.49, 0.25-0.75). Overall, these data provide some modest evidence for interactions between dietary fat intake and genetic variation in genes involved in eicosanoid metabolism and colorectal cancer risk.

The influence of physical activity on lean mass accrual during adolescence: a longitudinal analysis

During childhood, physical activity is likely the most important modifiable factor for the development of lean mass. However, the effects of normal growth and maturation must be controlled. To distinguish effects of physical activity from normal growth, longitudinal data are required. One hundred nine boys and one hundred thirteen girls, participating in the Saskatchewan Pediatric Bone Mineral Accrual Study, were repeatedly assessed for 6 yr. Age at entry was 8–15 yr. Stature, body mass, and physical activity were assessed biannually. Body composition was assessed annually by dual-energy X-ray absorptiometry. Physical activity was determined using the physical activity questionnaires for children and adolescence. Biological age was defined as years from age of peak height velocity. Data were analyzed using multilevel random-effects models. In boys, it was found that physical activity had a significant time-dependent effect on lean mass accrual of the total body (484.7 ± 157.1 g), arms (69.6 ± 27.2 g), legs (197.7 ± 60.5 g), and trunk (249.1 ± 91.4 g) ( P < 0.05). Although the physical activity effects were similar in the girls (total body: 306.9 ± 96.6 g, arms: 31.4 ± 15.5 g, legs: 162.9 ± 40.0 g, and trunk: 119.6 ± 58.2 g; P < 0.05), boys for the same level of activity accrued, depending on the site, between 21 and 120% more absolute lean mass (g). In conclusion, habitual physical activity had a significant independent influence on the growth of lean body mass during adolescence, once biological maturity and stature were controlled.

Genetic polymorphisms in one-carbon metabolism: associations with CpG island methylator phenotype (CIMP) in colon cancer and the modifying effects of diet

This study investigated associations between CpG island methylator phenotype (CIMP) colon cancer and genetic polymorphisms relevant to one-carbon metabolism and thus, potentially the provision of methyl groups and risk of colon cancer. Data from a large, population-based case-control study (916 incident colon cancer cases and 1,972 matched controls) were used. Candidate polymorphisms in methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase (TS), transcobalamin II (TCNII), methionine synthase (MTR), reduced folate carrier (RFC), methylenetetrahydrofolate dehydrogenase 1 (MTHFD1), dihydrofolate reductase (DHFR) and alcohol dehydrogenase 3 (ADH3) were evaluated. CIMP- or CIMP+ phenotype was based on five CpG island markers: MINT1, MINT2, MINT31, p16 and MLH1. The influence of specific dietary factors (folate, methionine, vitamin B(12) and alcohol) on these associations was also analyzed. We hypothesized that polymorphisms involved in the provision of methyl groups would be associated with CIMP+ tumors (two or more of five markers methylated), potentially modified by diet. Few associations specific to CIMP+ tumors were observed overall, which does not support the hypothesis that the provision of methyl groups is important in defining a methylator phenotype. However, our data suggest that genetic polymorphisms in MTHFR 1,298A > C, interacting with diet, may be involved in the development of highly CpG-methylated colon cancers. AC and CC genotypes in conjunction with a high-risk dietary pattern (low folate and methionine intake and high alcohol use) were associated with CIMP+ (OR = 2.1, 95% CI = 1.3-3.4 versus AA/high risk; P-interaction = 0.03). These results provide only limited support for a role of polymorphisms in one-carbon metabolism in the etiology of CIMP colon cancer.

Assessment of a dietary questionnaire in cancer patients receiving cytotoxic chemotherapy

PURPOSE

Few studies have examined the influence of diet on survival and chemotherapy-associated toxicities in patients with cancer. Although several comprehensive dietary questionnaires have been validated and calibrated in healthy populations, similar studies have not been performed among cancer patients.

METHODS

Two hundred patients with colorectal, breast, or neuroendocrine cancer undergoing treatment with cytotoxic chemotherapy completed a self-administered, 131-item, semiquantitative food frequency questionnaire. Using the questionnaire, we calculated dietary intakes of carotenoids, tocopherols, and fatty acids, and correlated these values with relevant biomarkers measured in simultaneously collected plasma specimens.

RESULTS

The Pearson correlation coefficients for various carotenoids as measured by the questionnaire, with the corresponding measurements in plasma specimens, ranged from 0.33 to 0.44 (all P < .001), adjusted for total energy intake, body mass index, age, sex, smoking status, and total plasma cholesterol. Similarly, the adjusted correlation between self-reported total vitamin E intake and plasma alpha-tocopherol was 0.34 (P < .001). Correlations between questionnaire and plasma measurements of trans-fat, eicosapentaenoic acid, and docosahexaenoic acid were 0.55, 0.29, and 0.42 (all P < .001), respectively. These levels of correlation are consistent with those reported in similar studies of self-reported diet in otherwise healthy populations.

CONCLUSION

Among patients with cancer receiving cytotoxic chemotherapy, questionnaire-based measurements of various micronutrients and dietary factors appeared to predict meaningful differences in the corresponding measurements in plasma specimens. This dietary questionnaire could offer an informative and practical means for assessing the influence of diet in cancer patients receiving chemotherapy.

Review of evaluation tools used to assess the impact of nutrition education on dietary intake and quality, weight management practices, and physical activity of low-income audiences

Nutrition education programs and social marketing campaigns frequently focus on low-income audiences with the goal of improving dietary intake and quality, weight management practices, and physical activity. The impact of nutrition education can be assessed by measuring change in relation to any or all of these broad variables. Unfortunately, little information is available concerning the reliability, validity, and sensitivity to change of measures used to assess these constructs with low-income audiences of adults and adolescents. This article reviews the literature and discusses the types of available measures that have been used and evaluated for the above audiences. It describes specific measures used to assess total diet, consumption of food groups from the Food Guide Pyramid, and behaviors related to weight management and physical activity. Overall, this review suggests that there is a critical need for additional development and evaluation of dietary quality measurement tools for low-income and minority audiences.

Differences in LDL oxidizability by glycemic status: the insulin resistance atherosclerosis study

OBJECTIVE

To investigate differences in LDL oxidizability by glycemic status within the Insulin Resistance Atherosclerosis Study cohort.

RESEARCH DESIGN AND METHODS

LDL oxidizability (lag time and oxidation rate) after exposure to copper was compared among 352 subjects with normal glucose tolerance (NGT), impaired glucose tolerance (IGT), newly diagnosed type 2 diabetes, and known type 2 diabetes.

RESULTS

After adjustment for age, clinic, ethnicity, sex, and smoking status, LDL oxidation rates differed by glycemic status (P = 0.001), with a strong trend (P = 0.0001) for reduced LDL oxidation rate with increasing extent and duration of glucose intolerance (2,378 +/- 54, 2,208 +/- 65, 2,145 +/- 71, and 2,115 +/- 48 arbitrary units [mean +/- SE] for NGT, IGT, newly diagnosed type 2 diabetes, and known type 2 diabetes, respectively). Differences in LDL oxidation rate among groups were relatively unaltered by adjustment for lipids and lipoproteins, hypertension, BMI, and waist-to-hip ratio (WHR) and remained significant even after further adjustment for dietary antioxidants and fatty acids, as well as medications. LDL lag times differed marginally by glycemic status (P = 0.058), with similar values for NGT, IGT, and newly diagnosed type 2 diabetes (57-60 min) but higher values for known type 2 diabetes (65 +/- 2). These differences were eliminated by further adjustment for lipids and lipoproteins, hypertension, BMI, and WHR.

CONCLUSIONS

We found that glycemic status influenced LDL oxidizability, with a paradoxical reduction in LDL oxidizability, as indicated by a lower LDL oxidation rate with increased extent and duration of glucose intolerance. This difference was only slightly attenuated by adjustment for relevant demographic, metabolic, dietary, and pharmacological factors that potentially influence LDL oxidation.

Measurement of dietary intake in the UNC Alumni Heart Study. University of North Carolina

BACKGROUND

Research needs to identify diet and disease associations to provide direction about effecting change in individuals with dietary behaviors that increase risk of chronic disease. Inclusion of dietary assessment in the University of North Carolina Alumni Heart Study (UNCAHS) provides the opportunity to prospectively investigate dietary intake and chronic disease associations with measures of personality and behavioral risk factors.

METHODS

Development of the UNCAHS food frequency questionnaire and nutrient intake of 4,443 middle-aged men and women is provided stratified by total fat and vitamin A intake within demographic and health behavior categories.

RESULTS

Alumni consume diets close to that recommended by current dietary guidelines. Both men and women have low calcium intake. Thirty-nine percent of the alumni consume diets with 30% of kilocalories from fat or less and 88% meet the RDA for vitamin A. Never smokers had lower fat diets and greater intakes of vitamin A than former or current smokers. Over 54% of alumni currently took vitamin/mineral supplements.

CONCLUSIONS

UNCAHS participants will be tracked as they approach older ages with apparently less risk for diet-related chronic diseases than many Americans. The psychosocial correlates of these eating behaviors will be evaluated as disease endpoints occur.