Table 3.
Determinants of weight loss in kilograms in 289 women randomized to the intervention group
| Determinants | β kg (95% CI) univariable | p | β kg (95% CI) multivariable | p |
|---|---|---|---|---|
| BMI (kg/m2) | 0.25 (0.08–0.42) | < 0.01 | 0.07 (− 0.14 to 0.28) | 0.51 |
| Duration of infertility (months) | 0.02 (0.00–0.03) | 0.03 | 0.02 (− 0.00 to 0.04) | 0.08 |
| Number of weight loss attempts in past 5 years | n.a. | < 0.01 | n.a. | 0.08 |
| None | [ref] | [ref] | n.a. | |
| 1 Attempt | 0.80 (− 1.09 to 2.69) | 0.40 | [ref] | [ref] |
| 2–3 Attempts | 0.47 (− 1.28 to 2.22) | 0.60 | − 0.83 (− 2.25 to 0.59) | 0.25 |
| 4–5 Attempts | 0.76 (− 1.10 to 2.62) | 0.42 | − 0.87 (− 2.45 to 0.71) | 0.28 |
| > 5 Attempts | 2.26 (0.57–3.95) | < 0.01 | 0.42 (− 0.98 to 1.82) | 0.56 |
| Stage of change: weight loss | n.a. | 0.001 | n.a. | 0.15 |
| Precontemplation | n.a. | n.a. | n.a. | n.a |
| Contemplation | − 2.21 (− 6.73 to 2.302) | 0.34 | − 1.84 (− 6.41 to 2.73) | 0.43 |
| Preparation | − 1.11 (− 2.35 to 0.13) | 0.08 | − 0.16 (− 1.55 to 1.24) | 0.83 |
| Action | − 1.90 (− 2.80 to − 0.99) | < 0.001 | − 1.12 (− 2.15 to − 0.09) | 0.03 |
| Maintenance | [ref] | [ref] | [ref] | [ref] |
| Previous support by a dietician | 1.37 (0.48–2.27) | < 0.01 | 0.94 (0.01–1.87) | 0.047 |
Bold value indicates a statistically significant difference with a p-value less than 0.05
Results of uni- and multivariable mixed-effect regressions models on determinants of weight loss. With correction for baseline BMI and including a random intercept. Mixed-effect regression analysis was performed to identify determinants of lifestyle change on the repeated measurements of the continuous weight loss outcome. All determinants with a p value < 0.05 were entered in the multivariable model. We censored weight measurements of women with an ongoing pregnancy from the conception date onwards. The results of the mixed-effect regression models are reported as regression coefficients (β) and the corresponding 95% CI, and indicate mean change throughout the intervention period. A negative number indicates additional weight loss; a positive number indicates less weight loss. Full univariable mixed-effect regression results are provided in Additional Table S2. The stage of change for weight loss was derived from the following question: ‘Have you been trying to lose weight?’, with possible answer categories: (1) Precontemplation: ‘No, and I am not planning to do so in the coming 6 months’, (2) Contemplation: ‘No, but I am planning to do so in the coming 6 months’, (3) Preparation: ‘No, but I am planning to do so in the coming month’, (4) Action: ‘Yes, I have been trying to lose weight for less than 6 months’ and (5) Maintenance: ‘Yes, I have already been trying to lose weight for more than 6 months’
β regression coefficient, CI confidence interval, BMI body mass index, n.a. not applicable