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Url Link
The hyperlink to my paper’s website.
Methods
The study was a randomised, single-centre, doubleblind, placebo-controlled trial including healthcare professionals employed in psychiatric and somatic hospitals. The participants were suffering from moderate seasonality with SAD symptoms.
Participants of the study are healthcare workers from various psychiatric and regular hospitals who have seasonal affective disorder (SAD). Participants were randomly selected to be part of a control group (given a placebo) and a treatment group (given a vitamin D supplement). Neither the participants nor the people doing the study know who is getting a placebo or who is getting a supplement in order to test the efficacy of vitamin D supplementation on treating SAD.
Introduction
Indoor work has been hypothesized as a risk factor for mood difficulties among civil servants in a Danish crosssectional study (latitude 55-57N°), a significant risk reduction (odds ratio = 0.63) being found in outdoor workers (>2 hours/day). Thus, indoor work might be a significant risk factor for SAD, since indoor work is by far the most prevalent form of work among the total work force at temperate latitudes
People who work indoors in Denmark were researched in another study and were found to be at a higher risk of developing mood disorders. Thus, people who work indoors, which is common in temperate locations like Denmark, Canada, and the USA, are believed to be at a greater risk of developing SAD.
Results
Of the 43 participants randomised, 22 received 70 μg of active vitamin D, and 21 received placebo. 34 completed the study, and data were collected for the primary, secondary and exploratory outcomes during winter-spring (January, February, March 2012)
A total of 43 people participated in the study, with 22 of them receiving a vitamin D supplement and 21 of them receiving a placebo. Only 34 of those 43 people got through the entire study. The primary outcome is the participant’s responses on questionnaires about mood and depression levels. The secondary outcome is the participants responses on questionnaires about their well-being. The exploratory outcome was information collected about a participant’s weight, waist circumference, blood pressure, and absenteeism from work. This information was collected by researchers during January, February, and March of 2012.
Discussion
[T]he overall most significant finding in this study was that vitamin D had no effect on SAD symptoms.
The study data, once analyzed by the researchers, indicated there was no measurable improvement in mood or symptoms between the placebo group and the treatment group. There is no indication according to this study that vitamin D supplementation can help people who suffer from SAD.
Future Directions
This study was limited to the later winter months after the winter solstice (January to March 2012) when the amount of sunlight during the day is increasing. This could lessen the severity of the symptoms of SAD and cause participants to underreport the severity of the disorder on their mood. A possible future direction could be the lengthening of the data gathering period from October to March (inclusive) to research whether the severity of SAD symptoms, and the possible alleviation of those symptoms could be affected by the length of available daylight pre- and post-winter solstice.
Difficult Material
There was a lot of confusing acronyms strewn about the paper, like: SPAQ-SAD, CRP, PTH, WHO-5. There was a handy abbreviation chart at the end of the paper that explained what the acronyms letters meant, but I only found it at the end after reading the entire paper which wasn’t helpful to make sense of all the jargon. Even then, I feel like some of the abbreviations on that list were referencing questionnaire formats that I’m unfamiliar with, so I’m unsure how rigorous the methods used in this study are at assessing SAD.
I did see a lot of issues with this study and its generalizability to SAD and vitamin D supplementation. For one, the study was extremely small, with only 34 participants. And despite the study explaining that SAD seems to affect females more than males, there is no breakout of the data looking at that trend, nor any discussion on the number of women or men who even participated. The study also gathered its participants from people who volunteered, so this may not be a reliable way to people who have significant, severe SAD, versus people who may be self-diagnosing and may not meet clinical standards for disorder diagnosis. The study also excluded people who have significantly depleted serum vitamin D levels and may benefit the most from supplementation affecting the symptoms of SAD. And as I discussed above, the study was extremely limited in duration and involved a period where the most severe effects of SAD would be expected to naturally start to resolve, as the amount of daylight starts to increase after the winter solstice.
URL link:
Paste the hyperlink to the website containing the original posting about the paper, NOT to the scientific paper itself (provide hyperlink to either the public posting webpage, or the Moodle forum webpage):
https://biol1592.trubox.ca/2025/11/28/frandsen_pareek_hansen_2014/
Additional Translation:
From which section of the paper is this passage?
Method
Paste quoted text on the next line. Do not include quotation marks or a bullet mark:
The participants were randomized to either 70 μg vitamin D or placebo for a period of 12 weeks during the winter period. The dose of 70 μg vitamin D was chosen in accordance with the previous study by Jorde et al.
Write your translation on the next line:
The researchers randomly assigned participants to receive either 70 micrograms of vitamin D or a placebo for 12 weeks during the winter. The amount of vitamin D given was based on a dosage that had been used in an earlier study conducted by Jorde and colleagues.
Additional Future Directions:
What future research do you think should follow up on this work?
A future study could focus specifically on participants who are clinically diagnosed with Seasonal Affective Disorder and who also have confirmed vitamin D deficiency before supplementation begins. Researchers could also test multiple dosage levels of vitamin D to determine whether higher or individualized doses produce measurable improvements in SAD symptoms.
Difficult Material (from original poster or subsequent student):
What did the previous poster state was difficult to understand? (Copy and paste their statement here.):
There was a lot of confusing acronyms strewn about the paper, like: SPAQ-SAD, CRP, PTH, WHO-5. There was a handy abbreviation chart at the end of the paper that explained what the acronyms letters meant, but I only found it at the end after reading the entire paper which wasn’t helpful to make sense of all the jargon. Even then, I feel like some of the abbreviations on that list were referencing questionnaire formats that I’m unfamiliar with, so I’m unsure how rigorous the methods used in this study are at assessing SAD.
Try to explain the difficult materials to the original poster as best as you can. (This is where you can help them understand what they found difficult.)
The acronyms mentioned in the paper refer to standardized questionnaires and biological markers used in clinical research. For example, SPAQ-SAD is a tool used to measure seasonal mood changes, and WHO-5 is a short questionnaire assessing general well-being. CRP (C-reactive protein) and PTH (parathyroid hormone) are biological markers measured in blood tests. Although these abbreviations may seem confusing at first, they are commonly used tools in medical research to ensure consistency and reliability when measuring symptoms and physiological factors.
New Difficult Material (according to you):
What did you not understand about this paper that someone else may be able to help you with? Or, if you understood everything, what did you find most challenging to understand?
I found it most difficult to evaluate whether the study had enough statistical power to detect a meaningful effect. Because the sample size was small and many participants did not complete the study, it is unclear whether the lack of significant findings truly means vitamin D has no effect, or whether the study simply did not include enough participants to detect a difference.