Table 5.
Pooled comorbidity proportion by average age of participants
| Associated condition category | Associated condition | Average age ≤ 40.3 (65 studies) | Average age ≥ 40.4 (66 studies) | Heterogeneity between groups |
|---|---|---|---|---|
| Cancers | Any cancer | 2 % (2–3 %) | 2 % (0–5 %) | p = .077 |
| Cardiovascular diseases | Ischemic heart disease | 6 % (3–9 %) | 6 % (3–10 %) | p = .908 |
| Stroke/Cerebrovascular | 3 % (2–5 %) | 4 % (1–8 %) | p = .591 | |
| Hypertension | 13 % (9–17 %) | 30 % (27–32 %) | p < .001 | |
| Atrial fibrillation and flutter | 2 % (1–3 %) | 1 % (0–3 %) | p = .813 | |
| Digestive diseases | Upper digestive system diseases | 14 % (6–24 %) | 3 % (1–7 %) | p = .010 |
| Irritable bowel syndrome | 6 % (4–8 %) | 19 % (13–28 %) | p < .001 | |
| Metabolic and kidney diseases | Diabetes mellitus | 5 % (4–7 %) | 6 % (4–8 %) | p = .709 |
| Chronic kidney disease | 0 % (0–0 %) | 5 % (1–11 %) | p = .007 | |
| Obesity | 21 % (15–29 %) | 19 % (14–26 %) | p = .681 | |
| Hyperlipidemia | 10 % (3–20 %) | 15 % (9–21 %) | p = .359 | |
| Hypercholesterolemia | 9 % (2–22 %) | 38 % (30–36 %) | p < .001 | |
| Thyroid diseases | 13 % (4–24 %) | 12 % (2–26 %) | p = .937 | |
| Musculoskeletal disorders | Arthritis | 14 % (12–15 %) | 10 % (6–16 %) | p = .470 |
| Back pain | 67 % (60–74 %) | 41 % (5–84 %) | p = .259 | |
| Fibromyalgia | 29 % (20–38 %) | 13 % (0–48 %) | p = .382 | |
| Neurological disorders | Parkinson disease | – | 1 % (1–2 %) | – |
| Idiopathic epilepsy | 2 % (1–4 %) | 2 % (1–3 %) | p = .852 | |
| Sleep disorder | 60 % (40–79 %) | 34 % (28–39 %) | p = .013 | |
| Restless leg syndrome | 32 % (19–46 %) | 11 % (6–19 %) | p = .005 | |
| Mental health disorders | Depressive disorders | 31 % (22–41) | 19 % (15–22 %) | p = .011 |
| Bipolar disorder | 1 % (1–2 %) | 6 % (0–18 %) | p = .132 | |
| Anxiety disorders | 25 % (18–34 %) | 24 % (21–28 %) | p = .841 | |
| Post-traumatic stress disorder | 12 % (10–14 %) | 14 % (1–36 %) | p = .809 | |
| Respiratory diseases | Asthma | 4 % (2–7 %) | 9 % (4–14 %) | p = .056 |
| Chronic obstructive pulmonary disease | 2 % (1–3 %) | 12 % (12–13 %) | p < .001 | |
| Sense organ disease | Any sense organ diseases | 49 % (38–60 %) | 29 % (5–62 %) | p = .266 |
| Skin and subcutaneous disease | Any skin and subcutaneous disease | – | 5 % (3–7 %) | – |
| Substance use disorders | Any substance use disorder | 2 % (0–5 %) | 8 (1–22 %) | p = .164 |
| Other NCDs | Oral disorders | 66 % (57–74 %) | 71 % (0-100 %) | p = .931 |
| Hemoglobinopathies and hemolytic anemias | – | 1 % (1–2 %) | – | |
| Other disorders (Congenital birth defects & Gynecological diseases) | 58 % (48–68 %) | 6 % (4–9 %) | p < .001 | |
| Allergies | 32 % (30–34 %) | 19 % (7–34 %) | p = .085 |