Purpose and/or primary question
The common and primary question that this article try’s to put across is, Does higher-dose vitamin D supplementation improve bone mineral density (BMD, measured using high-resolution peripheral quantitative computed tomography) and bone strength (measured as failure load)? Never the less the research is objected to assess the dose-dependent effect of vitamin D supplementation on volumetric bone mineral density (BMD) and strength.
Primary study aim (should inform study purpose)
Few studies have assessed the effects of daily vitamin D doses at or above the tolerable upper intake level for 12 months or greater, yet 3% of US adults report vitamin D intakes of at least 4000 IU per day. This study is so focused on assessing the volumetric bone mineral density (BMD), and intensity dosage dependent effect of the vitamin D supplementation.
Secondary study aim(s)
A 3-year randomized clinical trial examined the effect of 3 daily doses of vitamin D on volumetric BMD in healthy adults aged 55 to 70 years. The study found a negative dose-response relationship. High-dose vitamin D without extra calcium supplementation has been associated with increased levels of the active vitamin D metabolite 1, 25(OH)2 vitamin D (calcitriol), and an increase in CTx. This might reduce PTH-mediated bone formation, which when combined with a vitamin D–mediated direct effect on osteoclast activity could result in a dose-related accelerated decline in observed BMD.
The design of the sample is a mechanism by which the research procedure and the mathematical analysis are coordinated to ensure that either null assumptions are approved or dismissed. The design of any study is more critical than reviewing the findings, because a study with poor design cannot be retrieved, whereas a study with better analysis can be checked so that it can draw a valid conclusion. Instead, the study’s architecture defines how best to analysis the generated results. Thus relying primarily upon the research method, the scientific merit and the credibility of the evidence from the report.
There are many study designs to choose from within two broad categories of observational and interventional studies. Each design has its own strengths and weaknesses, and the need to understand these limitations is necessary to arrive at correct study conclusions. This manuscript is meant to provide an overview of study design types, strengths and weakness of common observational and Interventional study designs.
For this article the type of sampling used is stratified sampling, Stratified sampling means the population is split into subpopulations, which may vary greatly. It helps you to draw accurate conclusions by ensuring that the sample accurately corresponds to any subgroup. You split the population according to the appropriate characteristic (i.e. gender, age group, income bracket, work role) with the use of this sampling process. You measure the number of people sampled from each subgroup according to the average proportion of the population. Then you pick a sample from each subgroup using random or systematic samples.
Variables that are measured in the study
The variables that the study involves itself in include, volumetric bone density: vitamin D supplementation:
Statistical analysis used to address primary study aim
This article is meant to help you build a predictive research method. The material provided in the present article is divided into three key sections: a summary of the terminology and principles used in data processing and a discussion of popular approaches used to summarize data from studies, as well as a process to help recognize applicable data in the context of the study. My goal here is to show the principal data analytical elements and give you the opportunity to start preparing this aspect of your studies. If you need additional knowledge and guidance, biostatistics experts, seminars, mathematical software packages and other tools will definitely bring to this subject more scope and breadth.
Most important results of the study
For stable adults, vitamin D therapy was statistically substantially decreased over three years at 4000 or 10 000 IU daily, compared to 400 IU daily; tibial BMD was slightly lower only on the 10 000 IU daily dosage. In either the radius or the tibia there were no substantial variations in bone strength. These results do not endorse a high-dose vitamin D bone health supplement; additional tests will be needed to assess if it is toxic.
Do study limitations make you feel as if these results may not be valid/reliable and therefore not appropriate to incorporate in caring for patients/families? Why or why not?
This study has several limitations. Degradation of 2 lots of the vitamin D solution administered to participants in the 10’000-IU per day group resulted in those participants receiving less than the designated dose. Participants with osteoporosis or with 25(OH) D levels of less than 30 nmol/L were excluded from this study. The effect of high-dose vitamin D supplementation on HR-pQCT measurements of volumetric BMD was in the opposite direction of the hypothesized effect.