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. 2019 Dec 20;12(1):30. doi: 10.3390/nu12010030

Correction: Schraders, K. et al. Quantitative Ultrasound and Dual X-ray Absorptiometry as Indicators of Bone Mineral Density in Young Women and Nutritional Factors Affecting It. Nutrients, 2019, 11, 2336

Katie Schraders 1, Giancarla Zatta 1, Marlena Kruger 2, Jane Coad 1, Janet Weber 1, Louise Brough 1, Jasmine Thomson 1,3,*
PMCID: PMC7019353  PMID: 31877671

The authors would like to make the following correction to our recent publication [1]. In the methods section (Section 2.6. Statistical Analysis), on page 3, the calculation of the sample size should read as follows:

This study is a subset of a larger observational study. Initially, we determined the sample size for a correlation between DXA and QUS [2] using a type 1 error rate at 5% and type 2 error at 80% with an expected correlation coefficient of at least 0.5 (a moderate effect size), which has been found in other studies. This suggested a sample size of 29 participants. However, we wanted to ensure that we had a representative population including those with low bone mineral density [3]. Thus, the sample size was based on the predicted population of 18–25-year-old females (267,100 in New Zealand in 2013) [4] with an estimated 10% of women of that age having low bone mineral density (10% variability). Assuming a 95% confidence level and 10% precision (margin of error), the minimum sample size needed was 35 women. Factoring in for incomplete data sets/drop-outs between visits of 30%, a sample size of 50 women was required to ensure that 10% were classified as having low bone mineral density.

The authors would like to apologize for any inconvenience caused by this amendment. This amendment does not affect the results or conclusion of the manuscript in any way.

References

  • 1.Schraders K., Zatta G., Kruger M., Coad J., Weber J., Brough L., Thomson J. Quantitative Ultrasound and Dual X-Ray Absorptiometry as Indicators of Bone Mineral Density in Young Women and Nutritional Factors Affecting It. Nutrients. 2019;11:2336. doi: 10.3390/nu11102336. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Hulley S., Cummings S., Browner W., Grady D., Newman T. Designing Clinical Research: An Epidemiologic Approach. 4th ed. Lippincott Williams & Wilkin; Philadelphia, PA, USA: 2013. [Google Scholar]
  • 3.Charan J., Biswas T. How to calculate sample size for different study designs in medical research? Indian J. Psychol. Med. 2013;35:121–126. doi: 10.4103/0253-7176.116232. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Research New Zealand . Special Report on the 2013 Census of New Zealand’s Population and Dwellings. Research New Zealand; Wellington, New Zealand: 2014. [Google Scholar]

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