Table 1.
Characteristics of studies included in the qualitative synthesis.
| First author | Country | Study design | Mean age (SD) | Female (%) | Total sample size | Total no of cases with aggressive features, n (%) | BMI categories n (%) | Main Findings | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Normal weight | Overweight | Obese | ||||||||
| Advanced tumor-node-metastasis stage | ||||||||||
| Choi JS, 2014 | South Korea | RC | n/a | 87.4% | 612 a | 201 (32.8%) | 426 (69.6%) | 141 (23.0%) | 13 (2.1%) | A higher proportion of advanced TNM stages was found in the obese and overweight patients’ groups than the underweight and normal-weight groups. |
| Tresallet C, 2014 | France | RC | 49.9 ( ± 4.2) | 78.5% | 1216 | 252 (20.7%) | 684 (56.3%) | 356 (29.3%) | 176 (14.5%) | Advanced TNM stage, stage 3, and stage 4 were more frequent with increasing BMI (18% in the normal-weight group, 22% in the overweight group, and 27% in the obese group (p<0.018). |
| Tumour size | ||||||||||
| Tresallet C, 2014 | France | RC | 49.9 ( ± 4.2) | 78.5% | 1216 | 536 (44.1%) | 684 (56.3%) | 356 (29.3%) | 176 (14.5%) | Tumour size was equivalent among the three evaluated BMI groups. |
| Kim SK, 2016 | South Korea | RC | n/a | 78.2% | 5081 | 2518 (49.6%) | 3255 (64.1%) | 1582 (31.1%) | 244 (4.8%) | Higher BMI associated with larger tumours, women p<0.001, men p<0.002. |
| Harari A, 2012 | USA | RC | 48.2 | 72.9% | 443 | n/a | 175 (39.5%) | 141 (31.8%) | 99 (28.7%) | Obese patients reported larger tumors. |
| Extrathyroidal extension | ||||||||||
| Choi JS, 2014 | South Korea | RC | n/a | 87.4% | 612 a | 299 (48.9%) | 426 (69.6%) | 141 (23.0%) | 13 (2.1%) | In PTMC patients, BMI was associated with ETE. |
| Kim SH, 2015 | Japan | RC | 47 ( ± 11.7) | 84% | 716 | 133 (19.6%) | 481 (67.2%) | 202 (28.2%) | 33 (4.6%) | ETE was 16,8% in the group of patients with BMI < 24.9, 22.8% in the group of patients with BMI 25-29.9, and 18.2% in patients with BMI ≥ 30 (p=0.19). |
| Tresallet C, 2014 | France | RC | 49.9 ( ± 4.2) | 78.5% | 1216 | 299 (24.6%) | 684 (56.3%) | 356 (29.3%) | 176 (14.5%) | Obese patients had a greater rate of microscopic ETE in patients with BMI < 30 (32% vs. 23%, p<0.016). |
| Multifocality | ||||||||||
| Choi JS, 2014 | South Korea | RC | n/a | 87.4% | 612 a | 189 (30.9%) | 426 (69.6%) | 141 (23.0%) | 13 (2.1%) | Multifocality were predictive factors of advanced stage regardless of BMI in PTMC. |
| Tresallet C, 2014 | France | RC | 49.9 ( ± 4.2) | 78.5% | 1216 | 488 (40.1%) | 684 (56.3%) | 356 (29.3%) | 176 (14.5%) | Multifocality rate was equivalent between the three BMI groups. |
| Lymph node metastasis | ||||||||||
| Choi JS, 2014 | South Korea | RC | n/a | 87.4% | 612 a | 188 (30.7%) | 426 (69.6%) | 141 (23.0%) | 13 (2.1%) | The rates of metastatic LN did not differ among BMI groups in PTMC patients. |
| Zaman SU, 2018 | Pakistan | RC | 44.6 ( ± 14.3) | 71.7% | 53 | 24 (45.3%) | 28 (52.8%) | n/a | 25 (47.1%) | Higher frequencies of LN stage tumours in the obese group were reported but were not statistically significant. |
| Kim SH, 2015 | Japan | RC | 47 ( ± 11.7) | 84% | 716 | 342 (47.8%) | 481 (67.2%) | 202 (28.2%) | 33 (4.6%) | Higher BMI was associated with more lymph node involvement (p<0.004) in patients < 45 years of age. |
| Tresallet C, 2014 | France | RC | 49.9 ( ± 4.2) | 78.5% | 1216 | 244 (20.1%) | 684 (56.3%) | 356 (29.3%) | 176 (14.5%) | BMI was a risk factor for neck LN metastases (lateral or central compartment) and LN extracapsular spread when adjusted for confounding factors. |
RC, Retrospective Cohort Study; SD, Standard Deviation; PTC, Papillary Thyroid Carcinoma; PTMC, Papillary Thyroid Micro carcinoma; n/a, not assessed; BMI, Body Mass Index; ETE, Extrathyroidal extension; LN, Lymph node; TNM; tumor-node-metastasis.
a
Patients with PTMC.