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Rising trend in vitamin D status from 1993 to 2013: dual concerns for the future.

McKenna MJ, Murray BF, O'Keane M, Kilbane MT - Endocr Connect (2015)

Bottom Line: We retrieved all results of serum 25OHD from 1993 to 2013 (n=69 012) that was trimmed to one sample per person (n=43 782).The yearly average 25OHD increased from 36.1 nmol/l in 1993 to 57.3 nmol/l in 2013.The ARIMA model was a good fit for the 25OHD time series; it forecasted monthly average 25OHD up to the end of 2016 with a positive stationary R(2) of 0.377.

View Article: PubMed Central - PubMed

Affiliation: Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland mjmckenn@iol.ie.

No MeSH data available.


Related in: MedlinePlus

Forecast of average monthly 25OHD levels for 2014–2016 based on the ARIMA model. Predicted 25OHD is depicted in red that is based on ARIMA modelling of monthly average 25OHD as depicted in light green.
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fig4: Forecast of average monthly 25OHD levels for 2014–2016 based on the ARIMA model. Predicted 25OHD is depicted in red that is based on ARIMA modelling of monthly average 25OHD as depicted in light green.

Mentions: Visual inspection of the sequence chart of the monthly average 25OHD time series demonstrated an upward trend, seasonality in the series and a reduced variation in the data over time (Fig. 3). The latter observation was consistent with an increase in sample size over time that narrows the CIs. In order to visualize better the pattern of the data, the natural variation was suppressed by smoothing the time series using a 4253H smoother; the seasonality of the data is more apparent as well as the upward trend (Fig. 3). The ARIMA model was superimposed on the original data (Fig. 4). The model does not attempt to fit the first 12 months of the data due to the fact that the model is seasonal and requires this initial information to begin the model. As can be seen in the sequence chart, it takes into account the seasonality of the data. It can be seen that the model fits the data. The residuals were plotted on a sequence chart (figure not shown). The mean value of the residuals was −0.39 (CI: −0.51 to 1.29) nmol/l but the distribution lacked normality (P=0.003). Following removal of the outliers, the mean value of the residuals was −0.03 (CI: −0.84 to 0.78) nmol/l and it passed the test of normality (P=0.200). The rebuilt model using data from 1993 to 2010 predicted accurately the monthly values through 2011, 2012, and 2013 (figure not shown).


Rising trend in vitamin D status from 1993 to 2013: dual concerns for the future.

McKenna MJ, Murray BF, O'Keane M, Kilbane MT - Endocr Connect (2015)

Forecast of average monthly 25OHD levels for 2014–2016 based on the ARIMA model. Predicted 25OHD is depicted in red that is based on ARIMA modelling of monthly average 25OHD as depicted in light green.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496526&req=5

fig4: Forecast of average monthly 25OHD levels for 2014–2016 based on the ARIMA model. Predicted 25OHD is depicted in red that is based on ARIMA modelling of monthly average 25OHD as depicted in light green.
Mentions: Visual inspection of the sequence chart of the monthly average 25OHD time series demonstrated an upward trend, seasonality in the series and a reduced variation in the data over time (Fig. 3). The latter observation was consistent with an increase in sample size over time that narrows the CIs. In order to visualize better the pattern of the data, the natural variation was suppressed by smoothing the time series using a 4253H smoother; the seasonality of the data is more apparent as well as the upward trend (Fig. 3). The ARIMA model was superimposed on the original data (Fig. 4). The model does not attempt to fit the first 12 months of the data due to the fact that the model is seasonal and requires this initial information to begin the model. As can be seen in the sequence chart, it takes into account the seasonality of the data. It can be seen that the model fits the data. The residuals were plotted on a sequence chart (figure not shown). The mean value of the residuals was −0.39 (CI: −0.51 to 1.29) nmol/l but the distribution lacked normality (P=0.003). Following removal of the outliers, the mean value of the residuals was −0.03 (CI: −0.84 to 0.78) nmol/l and it passed the test of normality (P=0.200). The rebuilt model using data from 1993 to 2010 predicted accurately the monthly values through 2011, 2012, and 2013 (figure not shown).

Bottom Line: We retrieved all results of serum 25OHD from 1993 to 2013 (n=69 012) that was trimmed to one sample per person (n=43 782).The yearly average 25OHD increased from 36.1 nmol/l in 1993 to 57.3 nmol/l in 2013.The ARIMA model was a good fit for the 25OHD time series; it forecasted monthly average 25OHD up to the end of 2016 with a positive stationary R(2) of 0.377.

View Article: PubMed Central - PubMed

Affiliation: Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland Metabolism LaboratoryDepartment of EndocrinologySt Vincent's University Hospital, Elm Park, Dublin 4, IrelandSchool of Medicine and Medical SciencesUniversity College Dublin, Belfield, Dublin 4, Ireland mjmckenn@iol.ie.

No MeSH data available.


Related in: MedlinePlus