Date of Award

Spring 5-11-2018

Degree Type


Degree Name

Master of Public Health (MPH)


Public Health

First Advisor

Dr. Ike Okosun

Second Advisor

Dr. Barbara Yankey


BACKGROUND: Major depressive disorder (major depression) is a disabling mental illness that impairs mood, reduces physical functioning, and causes emotional distress. Depression studies often focus on adolescents and young adults or older adults, but evidence suggests that the most severe consequences of this illness increasingly affect those in the middle (ages 40-64).

OBJECTIVE: This study examines the individual association between three health determinants (social support systems, health status, and access to health insurance) and major depressive symptoms among middle-aged adults. Also, factors such as demographic factors, socioeconomic status, military service, risky behaviors, and health-promoting behaviors were evaluated for their associations with depression.

METHODS: This cross-sectional study utilizes secondary data from the National Health and Nutritional Examination Survey (NHANES) from the 2007-2008 and 2013-14 cycles. The statistical analysis was performed using SAS. Univariate logistic regression was used to determine the association between social support, health status, and health insurance and five depressive symptoms. Then logistic regression analyses were performed between each determinant, two depressive symptoms (feeling bad and suicidality), and adjusted for the

RESULTS: The sample included 3782 adults over 40 years old in 2007-2008 and 3627 in 2013-2014. The population was subset into young middle age, older middle age, and older adults to better characterize the age groups. The univariate logistic regression analyses indicate a statistically significant relationship between each determinant and the five depressive symptoms except among one factor in 2007-2008 and two in 2013-14. The adjusted logistic regression results are mixed. In reviewing the odds ratio results, health status has a strong statistically significant association with each depressive symptom. Health insurance generally does not show statistically significant associations. Social support is statistically associated with feeling bad, but not suicidality when the covariates are included. These findings are consistent with both cycles of data.

CONCLUSION: This study finds that lack of social support and poor health status predict higher levels of low mood in a national sample of adults over 40, particularly those in middle age. Health status also associates strongly with suicidal thoughts. Although health insurance is not shown to be associated with clinical depression symptoms in this study, additional research is warranted considering the recent changes in national health insurance coverage.