Research Methods - 25-hydroxyvitamin D and depressive symptoms

Running head: RESEARCH METHODS 1
Research Methods
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RESEARCH METHODS 2
1) The study aimed at determining the association between 25-hydroxyvitamin D and depressive
symptoms among older adults. Hypovitaminosis D is a condition that is common among senior
adults and is caused by the deficiency in Vitamin D which has further been associated with poor
health and chronic diseases (Stewart & Hirani, 2010). It is therefore suggested that
Hypovitaminosis D is likely to be a contributing factor to depression among older adults
(Milaneschi et al., 2010).
2) Population-based cohort study. This study design has multiple strengths. The outcomes of
such a study design apply to a specific population and thus eliminating selection bias. It also
allows the calculation of the population estimates, distribution and incidence rates. Additionally,
the design allows the unbiased study of the association of confounders to exposures and results
including those undefined in the initial research hypotheses (Strobe Initiative, 2014). On the
other hand, a population-based cohort study requires more time and is much costlier. It also
requires a larger sample size and is prone to misclassification and follow-up bias (Sorlie & Wei,
2011).
3) Women and men with 25(OH)D less than 50 nmol/l had increases in CES-D scores of 2.1 and
1.9 respectively. Low vitamin D in both men and women was a significant predisposing factor
for developing a depressed mood with a hazard ratio of 1.6 and 2.0 respectively. Therefore,
Hypovitaminosis D is a predisposing factor for depression among elderly adults with women
being affected the most. The outcome is thus consistent with the main objective because it shows
the association between the study variables as indicated in the objective
4) a) The study provides a basis for future research by exploring research that has not been
carried out by previous researchers. The study provides the strongest scientific evidence because
it identified the exposure before the results.
b) However, the study considers only one risk factor of depression among the elderly, yet there
exist other several aspects of vitamin D deficiency that influences depression.
5) The discussion and conclusion section of the study has been integrated effectively. The
current results have been examined in the context of current research knowledge. For instance,
the section cites the relevant findings of previous studies on relatively similar research and then