Table 1. Top-20 frequently occurring keywords.
| ID | 20 years | 1993–1997 | 1998–2002 | 2003–2007 | 2008–2012 |
|---|---|---|---|---|---|
| 1 | Body mass index | Insulin | Body mass index | Body mass index | Body mass index |
| 2 | Insulin resistance | Insulin resistance | Leptin | Insulin resistance | Metabolic syndrome |
| 3 | Diabetes | Weight loss | Insulin resistance | Morbid obesity | Diabetes |
| 4 | Metabolic syndrome | Hypertension | Diabetes | Diabetes | Insulin resistance |
| 5 | Children | Body mass index | Hypertension | Metabolic syndrome | Children |
| 6 | Hypertension | Diabetes | Weight loss | Bariatric surgery | Adolescents |
| 7 | Type 2 diabetes | Type 2 diabetes | Morbid obesity | Children | Type 2 diabetes |
| 8 | Morbid obesity | Body composition | Insulin | Weight loss | Bariatric surgery |
| 9 | Weight loss | Morbid obesity | Type 2 diabetes | Hypertension | Hypertension |
| 10 | Leptin | Risk factors | Children | Leptin | Weight loss |
| 11 | Bariatric surgery | Blood pressure | Risk factors | Type 2 diabetes | Physical activity |
| 12 | Adolescents | Adipose tissue | Body composition | Risk factors | Risk factors |
| 13 | Risk factors | Leptin | Adipose tissue | Adolescents | Inflammation |
| 14 | Physical activity | Exercise | Exercise | Physical activity | Adipose tissue |
| 15 | Adipose tissue | Children | Bariatric surgery | Body composition | Leptin |
| 16 | Insulin | Diet | Blood pressure | Adipose tissue | Morbid obesity |
| 17 | Body composition | Body weight | Diet | Gastric bypass | Epidemiology |
| 18 | Epidemiology | Cholesterol | Physical activity | Insulin | Exercise |
| 19 | Exercise | Vertical banded gastroplasty | Coronary artery disease | Epidemiology | Adiponectin |
| 20 | Inflammation | Zucker rats | Epidemiology | Exercise | Body composition |
Bold keywords have appeared in all four time periods (could be in different numerical order) as well as in the top-20 list of the aggregated time (i.e., 20 years)