Using NHANES as an example, this talk will briefly go over how to access, retrieve, and analyze publicly available data to investigate associations at a population level. I will walk through this process, the positives and negatives of working with this data, and discuss my findings relating cardiovascular disease, depression, and dietary inflammation.

Background: Studies suggest that cardiovascular disease (CVD) is a risk factor for depression. Both heart disease and stroke increase the risk of developing depressive symptoms and CVD increases vulnerability to late-life depression. Comorbid depression has serious health consequences, including decreased compliance with treatment and rehabilitation. Reducing the rate of comorbid depression may improve adherence and outcomes, while reducing disability and cost. Development of CVD and depression are also linked to increased systemic inflammation. It is thought that inflammatory processes occurring in CVD may increase susceptibility to depression. One potentially modifiable source of systemic inflammation is diet. We thus examined the association of inflammatory diet and CVD risk score on depression.

Methods: Using 2007-2012 National Health and Nutrition Examination Survey data, we calculated a Dietary Inflammatory Index score (DII), which represents the role of diet in systemic inflammation using the 24-hour dietary recall interview. Sex-specific CVD risk scores were calculated using a modified Framingham Risk equation. Current depression was determined using the Patient Health Questionnaire. Only participants with complete information and without prevalent CVD were included (n= 11,624). Pearson χ2 test and t-test were used for group comparisons. Using multivariable logistic regression, adjusted for age, sex, race, education, household income, supplement use, cholesterol-lowering medication, history of cancer, BMI and physical activity, we examined associations between: 1) CVD risk and current depression, 2) DII and current depression, adjusting for CVD risk, and 3) the joint effects of both CVD risk and DII on depression.

Results: Individuals with current depression were: younger, more likely to be female, non-white, have a high school degree or less, household income <$35,000, less physically active; and had higher: BMI, energy intake, CVD risk, and DII. In multivariable analysis, individuals with the highest two quartiles of CVD risk compared to those with the lowest quartile had increased odds of current depression (ORQ3:1.61, 95% confidence interval [CI]:1.24-2.10; ORQ4:1.47, CI:1.08-2.00). Individuals with the highest two quartiles of DII compared to those with the lowest quartile, while controlling for CVD risk, had increased odds of current depression (ORQ3:1.41, CI: 1.07-1.84; ORQ4:1.46, CI: 1.16-1.84). Individuals with both CVD and DII scores in the 4th quartile had a higher risk of depression than those with low DII and CVD risk (OR:2.21, CI: 1.57-3.13).

Conclusions: A pro-inflammatory diet is associated with increased odds of depression independently of CVD risk status. These results suggest that modifying the intake of pro-inflammatory foods may reduce the prevalence of depression with possible consequential benefits for those at high CVD risk.

Please RSVP by Friday, January 27th at noon.