Table 1. Descriptive characteristics of the study population, overall and by tertiles of weight change.
| Variable | Overall | T1a | T2 | T3 |
|---|---|---|---|---|
| n | 1632 | 544 | 544 | 544 |
| Women (%) | 98.41% | 98.90% | 98.35% | 97.98% |
| Age at baseline, years | 49.76 (8.85) | 49.91 (9.49) | 50.11 (8.54) | 49.25 (8.48) |
| Age at follow-up, years | 58.85 (9.17) | 58.03 (9.43) | 60.28 (8.79) | 58.23 (9.14) |
| years of follow-up, years | 9.09 (3.56) | 8·12 (3.83) | 10.16 (3·03) | 8.98 (3.49) |
| BMI at baseline, kg m–2 | 24.95 (4.17) | 25.40 (4.72) | 24.02 (3.42) | 25.41 (4.13) |
| BMI at follow-up, kg m–2 | 26.16 (4.58) | 24.44 (4.34) | 25.24 (3.37) | 28.81 (4.69) |
| BMI change per year, kg m–2 | 0.11 (0.31) | −0.17 (0.26) | 0.11 (0.06) | 0.39 (0.22) |
| Fibre intake, g day–1 | 20.4 (6.79) | 21.10 (6.98) | 20.33 (6.75) | 20.02 (6.62) |
| Kcal intake at baseline | 1994.86 (519.32) | 2030.46 (526.35) | 2015.66 (536.93) | 1927.63 (481.66) |
| Kcal intake at follow-up | 1822.56 (528.19) | 1858.63 (545.76) | 1827.53 (529.07) | 1770.76 (500.94) |
| Protein intake, g day–1 | 80.06 (22.88) | 81.02 (24.71) | 80.03 (22.54) | 79.14 (21.25) |
| Physical activity low, % | 16.63% | 19.36% | 14.56% | 16.28% |
| Saturated fat intake, g day–1 | 26.05 (10.25) | 26.70 (10.49) | 26.30 (10.76) | 24.98 (9.18) |
| Smoking (no:ex:yes) | 1019:505:108 | 353:155:36 | 339:172:33 | 327:179:39 |
| Use of PPIs | 14.15% | 13.05% | 14.15% | 15.26% |
| Indices of microbiome α-diversityb | ||||
| Shannon | 5.16 (0.72) | 5.21 (0.73) | 5.19 (0.73) | 5.07 (0.71) |
| Simpson | 0.92 (0.06) | 0.93 (0.06) | 0.92 (0.06) | 0.92 (0.06) |
| Observed OTU counts | 342.12 (97.45) | 346.25 (95.70) | 348.31 (102.93) | 331.79 (93.78) |
Mean (s.d.) reported unless indicated otherwise.
Abbreviations: BMI, body mass index; OTU, operational taxonomic unit; PPI, proton pump inhibitor; rRNA, ribosomal RNA.
a
T1, T2 and T3 represent, respectively, the first, second and third tertile of change in BMI over time adjusted for age, gender, baseline BMI, calorie intake and physical activity. T3 represents weight gain, whereas T1 represents weight loss.
b
The 16S rRNA sequencing data had been summarised to operational taxonomic units (OTUs).4 This table was rarefied to a depth of 10 000 OTUs per sample and three measures of gut microbiome alpha diversity were computed: Shannon, Simpson and observed OTU counts.