Statistical analysis
FM
REGRESSION
At 3 months, the expected weight reduction based on previous trials in Sweden [The primary outcome of this study was change in weight and markers of lipid and glucose metabolism at 3 and 12 months post-intervention. Lp(a) concentrations were classified by the laboratory as < 100 mg/L, > 850 mg/L or with an exact value if between 100 and 850 mg/L. In order to make the variable continuous for statistical purposes, concentrations < 100 mg/L were analysed as 99 mg/L and concentrations > 850 mg/L as 851 mg/L. Secondary outcomes were PPWR and changes in waist and hip circumference, body fat %, FM, FFM, systolic and diastolic blood pressure, hs-CRP and treatment-related changes in dietary intake and physical activity. PPWR was calculated by subtracting self-reported pre-pregnancy weight from measured weight at each study visit. Hs-CRP concentrations were processed similarly to Lp(a), with values > 10 mg/L analysed as 11 mg/L.Means and standard deviations (SD) are reported for normally distributed variables and their changes. Medians and ranges, first and third quartiles, or interquartile range (IQR) are reported for non-normally distributed variables and their changes.Differences in baseline characteristics between completers and non-completers were analysed by a two-sample T-test or Mann–Whitney nonparametric test and Fisher's exact test or Chi-Square test for categorical variables.The main results in this study are the differences between the diet and control groups in outcome measures across the three time points analysed with a linear mixed model using Stata 16.1 (StataCorp. 2019. Stata Statistical Software: Release 16. College Station, TX: StataCorp LLC). The results at 3 months are from analyses including all 3-month completers, while the results at 12 months are from analyses including only 12-month completers. A sensitivity analysis was performed with an intention-to-treat approach, including all participants regardless of attrition. The model included the variables time, treated as a factor, using baseline as reference, and the group-by-time interaction. In order to control for baseline variation in the outcome variable, the main effect of group was not included in the model [The difference in proportion of women in the diet and control groups who reached their pre-pregnancy weight (within 1 kg) or were below their pre-pregnancy weight at baseline and after 3 and 12 months was tested by use of a Chi-Square test and with logistic regression models adjusted for PPWR at baseline. IBM SPSS Statistics for Windows, version 26.0 (Armonk, NY), was used for analyses.