Lisa S. Brown

Associations of Carotid Artery Intima-Media Thickness (IMT) With Risk Factors and Prevalent Cardiovascular Disease Comparison of Mean Common Carotid Artery IMT With Maximum Internal Carotid Artery IMT

Objective. The goal of this study was to compare internal carotid artery (ICA) intima‐media thickness (IMT) with common carotid artery (CCA) IMT as global markers of cardiovascular disease (CVD). Methods. Cross‐sectional measurements of the mean CCA IMT and maximum ICA IMT were made on ultrasound images acquired from the Framingham Offspring cohort (n = 3316; mean age, 58 years; 52.7% women). Linear regression models were used to study the associations of the Framingham risk factors with CCA and ICA IMT. Multivariate logistic regression models and receiver operating characteristic (ROC) curve analysis were used to compare the associations of prevalent CVD with CCA and ICA IMT and determine sensitivity and specificity. Results. The association between age and the mean CCA IMT corresponded to an increase of 0.007 mm/y; the increase was 0.037 mm/y for the ICA IMT. Framingham risk factors accounted for 28.6% and 27.5% of the variability in the CCA and ICA IMT, respectively. Age and gender contributed 23.5% to the variability of the CCA IMT and 22.5% to that of the ICA IMT, with the next most important factor being systolic blood pressure (1.9%) for the CCA IMT and smoking (1.6%) for the ICA IMT. The CCA IMT and ICA IMT were statistically significant predictors of prevalent CVD, with the ICA IMT having a larger area under the ROC curve (0.756 versus 0.695). Conclusions. Associations of risk factors with CCA and ICA IMT are slightly different, and both are independently associated with prevalent CVD. Their value for predicting incident cardiovascular events needs to be compared in outcome studies.

Dietary Patterns and the Risk of Colorectal Cancer

Diet and lifestyle play a significant role in the development of colorectal cancer, but the full complexity of the association is not yet understood. Dietary pattern analysis is an important new technique that may help to elucidate the relationship. This review examines the most common techniques for extrapolating dietary patterns and reviews dietary pattern/colorectal cancer studies published between September 2011 and August 2012. The studies reviewed are consistent with prior research but include a more diverse international population. Results from investigations using a priori dietary patterns (i.e., diet quality scores) and a posteriori methods, which identify existing eating patterns (i.e., principal component analysis), continue to support the benefits of a plant-based diet with some dairy as a means to lower the risk of colorectal cancer, whereas a diet high in meats, refined grains, and added sugar appears to increase risk. The association between colorectal cancer and alcohol remains unclear.

Dietary Patterns of Women Are Associated with Incident Abdominal Obesity but Not Metabolic Syndrome

Data on the relationship between empirical dietary patterns and metabolic syndrome (MetS) and its components in prospective study designs are limited. In addition, demographic and lifestyle determinants of MetS may modify the association between dietary patterns and the syndrome. We prospectively examined the relationship between empirically derived patterns and MetS and MetS components among 1146 women in the Framingham Offspring/Spouse cohort. They were aged 25-77 y with BMI ≥18.5 kg/m(2) and free of cardiovascular disease, diabetes, cancer, and MetS at baseline, and followed for a mean of 7 y. Five dietary patterns, Heart Healthier, Lighter Eating, Wine and Moderate Eating, Higher Fat, and Empty Calorie, were previously identified using cluster analysis from food intake collected using a FFQ. After adjusting for potential confounders, we observed lower odds for abdominal obesity for Higher Fat [OR = 0.48 (95% CI: 0.25, 0.91)] and Wine and Moderate Eating clusters [OR = 0.28 (95% CI: 0.11, 0.72)] compared with the Empty Calorie cluster. Additional adjustment for BMI somewhat attenuated these OR [Higher Fat OR = 0.52 (95% CI: 0.27, 1.00); Wine and Moderate Eating OR = 0.34 (95% CI: 0.13, 0.89)]. None of the clusters was associated with MetS or other MetS components. Baseline smoking status and age did not modify the relation between dietary patterns and MetS. The Higher Fat and Wine and Moderate Eating patterns showed an inverse association with abdominal obesity; certain foods might be targeted in these habitual patterns to achieve optimal dietary patterns for MetS prevention.

Methodology for Adding Glycemic Index to the National Health and Nutrition Examination Survey Nutrient Database

Generating valid estimates of dietary glycemic index (GI) and glycemic load (GL) has been a challenge in nutritional epidemiology. The methodologic issues may have contributed to the wide variation of GI/GL associations with health outcomes observed in existing literature. We describe a standardized methodology for assigning GI values to items in the National Health and Nutrition Examination Survey (NHANES) nutrient database using the new International Tables to develop research-driven, systematic procedures and strategies to estimate dietary GI/GL exposures of a nationally representative population sample. Nutrient databases for NHANES 2003-2006 contain information on 3,155 unique foods derived from the US Department of Agriculture National Nutrient Database for Standard Reference versions 18 and 20. Assignment of GI values were made to a subset of 2,078 carbohydrate-containing foods using systematic food item matching procedures applied to 2008 international GI tables and online data sources. Matching protocols indicated that 45.4% of foods had identical matches with existing data sources, 31.9% had similar matches, 2.5% derived GI values calculated with the formula for combination foods, 13.6% were assigned a default GI value based on low carbohydrate content, and 6.7% of GI values were based on data extrapolation. Most GI values were derived from international sources; 36.1% were from North American product information. To confirm data assignments, dietary GI and GL intakes of the NHANES 2003-2006 adult participants were estimated from two 24-hour recalls and compared with published studies. Among the 3,689 men and 4,112 women studied, mean dietary GI was 56.2 (men 56.9, women 55.5), mean dietary GL was 138.1 (men 162.1, women 116.4); the distribution of dietary GI was approximately normal. Estimates of population GI and GL compare favorably with other published literature. This methodology of adding GI values to an existing population nutrient database utilized systematic matching protocols and the latest comprehensive data sources on food composition. The database can be applied in clinical and survey research settings where there is interest in estimating individual and population dietary exposures and relating them to health outcomes.

Dietary Patterns and Colorectal Cancer Risk: a Review of 17 Years of Evidence (2000–2016)

Purpose of ReviewColorectal cancer (CRC) is a global public health problem, with an estimated 1.4 million cases diagnosed worldwide in 2012. Evidence suggests that diet may be important for primary prevention.Recent FindingsThe 2017 WCRF/AICR Continuous Update Project on colorectal cancer concluded that there is convincing evidence linking several individual dietary factors with CRC risk but the evidence for dietary patterns was limited and inconclusive. In addition, previous reviews and meta-analyses have not critically synthesized various dietary patterns. This review synthesized data from dietary patterns studies over a 17-year period from 2000 to 2016.SummaryWe included 49 studies (28 cohort and 21 case-control) that examined the association of index-based and empirically derived dietary patterns and CRC risk. A synthesis of food group components comprising the different index-based and empirically derived patterns revealed two distinct dietary patterns associated with CRC risk. A “healthy” pattern, generally characterized by high intake of fruits and vegetables, whole grains, nuts and legumes, fish and other seafood, milk, and other dairy products, was associated with lower CRC risk. In contrast, the “unhealthy” pattern, characterized by high intakes of red meat, processed meat, sugar-sweetened beverages, refined grains, desserts, and potatoes was associated with higher CRC risk. It is notable that the number of food groups, the intake quantity, and the exact types of foods in each food group differed between populations, yet the two dietary patterns remained consistent across regions, especially in empirically derived patterns, an indication of the high reproducibility of these patterns. However, findings for CRC risk in both index-based and empirically derived patterns, differed by sex, with stronger associations among men than women; study design, a higher proportion of case-control studies reported significant findings compared to prospective studies. Consuming a dietary pattern high in fruits and vegetables and low in meats and sweets is protective against CRC risk. However, important questions remain about the mechanisms underlying differences by sex; life-course timing of exposure to dietary patterns; interaction of dietary patterns with the microbiome or with lifestyle factors including physical activity; and elucidation of subsite differences.

Nutrient database development: a historical perspective from the Framingham Nutrition Studies.

Food frequency questionnaires (FFQs) are commonly used in nutritional epidemiology to assess habitual eating habits. Development of an appropriate food and nutrient database is required for translating information derived from FFQs into estimates of nutrient intake, dietary quality, or for absolute or rank-ordered nutritional risk assessment. We discuss the procedures used recently in designing a historical nutrient database to analyze an FFQ administered in 1984-1988 to Framingham Offspring-Spouse Study members. This systematic approach should inform other research in the field. The self-administered 145-item Framingham FFQ is semi-quantitative with seven nonoverlapping response categories to determine annual consumption frequency. The database development process included selection of the US Department of Agricultures Nutrient Database for Standard Reference as the primary raw data source, expansion of the 145 FFQ line items to code individual foods to assign nutrient values, a selection process to match foods to appropriate nutrition codes for nutrient information, and a statistical model to calculate nutrient intakes. The historical database contains 449 foods and nutrient data for all 29 nutrients available in 1985. The adequacy with which an FFQ can provide reliable diet assessment data depends on the integrity of the underlying database. We outlined a systematic protocol to derive usual dietary intake from an FFQ using a robust nutrient database that is appropriate for the Framingham Offspring-Spouse Study FFQ and its assessment time-frame. The database can be updated to accommodate changes in the food supply and eating behaviors and creates a foundation for future nutrition research.

Effect of the Mediterranean Diet on Cancer Reduction

The Mediterranean diet is a plant-based dietary pattern characterized by high intake of olive oil, legumes, whole grains, fruit, vegetables, nuts, seeds, fish, and red wine. The diet has been linked to a decreased risk of developing many non-communicable diseases including several types of cancer. Although findings have been somewhat inconsistent, several large prospective cohort studies have shown an association between greater adherence to a traditional Mediterranean diet and lower overall cancer incidence. When specific forms of cancer are examined, current research suggests a stronger association with some types and a weaker or non-existent relationship with others. Existing literature is equivocal on the association between the Mediterranean diet and breast cancer, but studies are heterogeneous in menopausal status and tumor hormone receptor status. For colorectal cancer, data is reasonably consistent to suggest that adherence to the Mediterranean diet is associated with a reduced risk, although more studies are needed to confirm and refine the relationship. Evidence for a protective association of a Mediterranean dietary pattern on upper gastrointestinal cancers is quite consistent and suggests that the Mediterranean diet is associated with a reduction of risk. It should be noted that due to the small number of studies, more data, especially from non-European countries, is needed. Suggested mechanisms through which the Mediterranean diet may impact cancer initiation and proliferation include increased insulin sensitivity and reduction of excess insulin production, anti-inflammatory and antioxidant effects of the diet, high fiber content and an association with reduced risk of excess weight gain and obesity.