Abstract
BackgroundThere is a bilateral association between depression and diet. There is some evidence suggests that unhealthy diets are associated with an increased risk of developing depression but there is less evidence that depression is associated with worsening of diet. Understanding the role of depression on dietary behaviours may help reduce the risk of obesity, type 2 diabetes and cardiovascular disease (CVD). This is important because people with depression are at higher risk of obesity, type 2 diabetes and CVD. The overall aim of this thesis is to test whether depression is prospectively associated with an unhealthy diet, assessed in terms of quality and timing of ingestion.
Methods
This thesis consists of a literature review and a series of secondary analyses set in the MOVE IT cohort. MOVE IT is a randomised controlled trial (RCT) of the effectiveness of an intensive lifestyle intervention in 1750 adults at high risk of CVD in primary care. First a systematic review of observational studies of the association between depressive symptoms and risk of unhealthy diets was conducted. Second the association between depressive symptoms and dietary behaviour at baseline in the MOVE IT cohort was analysed. Third, the relationship between depressive symptoms at baseline and dietary intake two years later was assessed prospectively. Fourth the association between depressive symptoms and timing of food intake were studied prospectively over two years.
Results
The literature review suggests a possible correlation between depressive symptoms and the future risk of an unhealthy diet but there was a paucity of observational studies. At baseline in the MOVE IT cohort, there was a weak positive association between depressive symptoms and amount of CHO (p=0.006) and total sugar (p=0.034) and negative association between depressive symptoms and alcohol intake (p=0.012). There was a negative association between depressive symptoms and percentage of Kcals from CHO (p=0.016) and positive association between depressive symptoms and alcohol (p=0.008) at year one. After the second year of the study, this association with percentage of Kcal from CHO disappeared, and we found a positive association instead between depressive symptoms and saturated fat (p=0.033) and alcohol intake (p=0.035). No association was found between depressive symptoms and the type of food intake as well as timing of ingestion at each of the three timepoints.
Conclusion
There was limited evidence that depression is associated with a risk of unhealthy diets prospectively. Future studies focusing on depression cohorts rather than CVD cohorts may be more appropriate for quantifying the risks and patterns of ingestion.
Date of Award | 1 Dec 2019 |
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Original language | English |
Awarding Institution |
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Supervisor | Khalida Ismail (Supervisor) & Nicola Guess (Supervisor) |