Browsing by Subject "weight loss"
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(2019)Studies suggest that isolated impaired fasting glucose (iIFG) and isolated impaired glucose tolerance (iIGT) have distinct pathophysiologic phenotype, including differences in whole body insulin sensitivity. The present study was a sub-study of the PREVIEW intervention study, a three-year randomized trial in eight countries. Participants with either iIFG (n = 44) or iIGT (n = 38) who attended all clinical investigation days (0, 2, 6 and 12 months) in Sydney were included. Pre-diabetes as defined by the American Diabetes Association and BMI >25 were inclusion criteria. The aim was to determine if there was a difference in weight change between PREVIEW participants with iIGT or iIFG at any of the measurement points. In addition, we investigated if there were differences in change in fat mass, fat-free mass, HbA1c, blood lipids, insulin and C-peptide between participants with iIGT versus iIFG. A comparison of the mean changes showed that subjects with iIGT lost significantly less fat mass at 6 months than those with iIFG (-7.30, 95% CI [-8.89, -5.71] versus -9.57, 95% CI [-10.79, -8.35] kg, p = 0.027) and the difference remained significant (-6.30, 95% CI [-7.93, -4.67] versus -8.38, 95% CI [-10.99, -5.77] kg, p = 0.038) at 12 months. Furthermore, participants with iIGT regained fat (as fat %) at 12 months unlike participants with iIFG (-3.1, 95% CI [-4.08, -2.12] versus -4.9, 95% CI [-5.88, -3.92] %, p = 0.007). Reduction in HDL cholesterol was less in subjects with iIGT at 2 months than in those with iIFG (-0.08, 95% CI [-0.14, -0.02] versus -0.15, 95% CI [-0.21, -0.09] mmol/L, p = 0.011). Participants with iIGT lost less and regained more weight versus iIFG although the difference was not significant. No other changes were significant. In conclusion, the results support the hypothesis that participants with iIGT find it more difficult to lose fat mass and maintain the loss than those with iIFG. Studies are needed to confirm these findings and to determine the explanation for the difference in fat loss between iIGT and iIFG categories. As weight loss, including fat loss, is the dominant determinant of the reduced risk of T2DM in lifestyle interventions, actions to develop optimal weight loss methods for patients with different pre-diabetic statuses should be taken.
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(2018)Dropout is a serious problem in lifestyle interventions. Dropout is inadequately analyzed and inconsistently reported in weight loss and lifestyle intervention literature even though it is considered to be one of the most important aspects in assessing trial success. Attrition decreases the statistical power of the study, weakens the reliability and validity of the results, decreases generalizability of the outcomes, and deteriorates the accuracy of given recommendations. In addition, withdrawal leads to poor intervention outcomes and wasted resources. Dropout rates in weight loss intervention range from 7 to 90 percent. The analysis of this study comprised of the first two years of a three-year intervention called PREVIEW. The participants analyzed in this thesis (N = 2088) were overweight or obese prediabetic adults with an age of 52 ± 11.5 years at the start of the trial. Participants came from six European and two Australasian countries. Two thirds of the participants were women and the majority were Caucasian. The final prediction model was computed with multivariate logistic regression. Forty-four percent of the participants dropped out by year two. Dropouts were younger, had a higher baseline BMI, and lost less weight in the weight loss phase than the completers. Compared to Australia, the odds for dropping out were higher in the other countries analyzed. The odds for dropout in an ascending order were: Australia, Finland, New Zealand, the Netherlands, Bulgaria, the United Kingdom, Spain and Denmark. Compared to university education, the odds for dropping out were higher for participants with secondary vocational education, secondary school education, or education indicated as ‘other’. The findings of this thesis may be used in the development of similar trials and in public healthcare. In lifestyle intervention programs, special attention could be directed to individuals who are likely to drop out. In addition, as dropout is dependent of the explanatory variables, the results may also benefit future analysis of data from PREVIEW.
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