Table 2.
Associations between baseline fasting insulin concentrations and risk of developing obstructive sleep apnea
| Quintiles of fasting insulin |
Per doubling of fasting insulin | P-trend | |||||
|---|---|---|---|---|---|---|---|
| Q1 | Q2 | Q3 | Q4 | Q5 | |||
| NHS | |||||||
| Median (range)* | 1.7 (0.2–2.6) | 3.4 (2.6–4.2) | 5.0 (4.2–6.0) | 7.3 (6.0–9.0) | 12.6 (9.0–95.9) | — | — |
| Cases/N | 10/475 | 8/477 | 17/474 | 18/477 | 40/474 | — | — |
| Model 1† | 1.00 (ref) | 0.78 (0.31–2.02) | 1.54 (0.69–3.45) | 1.70 (0.76–3.79) | 3.85 (1.83–8.09) | 1.63 (1.32–2.00) | <0.0001 |
| Model 2‡ | 1.00 (ref) | 0.72 (0.28–1.86) | 1.20 (0.53–2.73) | 1.09 (0.48–2.50) | 1.66 (0.74–3.72) | 1.20 (0.96–1.51) | 0.11 |
| NHSII | |||||||
| Median (range)* | 2.5 (0.2–3.5) | 4.5 (3.5–5.4) | 6.3 (5.4–7.3) | 8.6 (7.3–10.8) | 15.3 (10.8–139.1) | — | — |
| Cases/N | 28/745 | 31/750 | 42/744 | 62/748 | 136/747 | — | — |
| Model 1† | 1.00 (ref) | 1.09 (0.64–1.84) | 1.38 (0.84–2.26) | 1.87 (1.17–2.98) | 3.86 (2.49–5.98) | 1.49 (1.32–1.68) | <0.0001 |
| Model 2‡ | 1.00 (ref) | 0.98 (0.58–1.66) | 1.14 (0.69–1.88) | 1.29 (0.80–2.09) | 1.87 (1.16–3.01) | 1.13 (0.99–1.29) | 0.07 |
| HPFS | |||||||
| Median (range)* | 2.9 (0.2–3.9) | 4.6 (3.9–5.5) | 6.4 (5.5–7.3) | 8.7 (7.3–10.4) | 13.5 (10.4–77.5) | — | — |
| Cases/N | 21/249 | 27/250 | 22/250 | 28/250 | 35/250 | — | — |
| Model 1† | 1.00 (ref) | 1.27 (0.69–2.34) | 1.00 (0.53–1.88) | 1.30 (0.71–2.39) | 1.62 (0.89–2.92) | 1.14 (0.94–1.38) | 0.19 |
| Model 2‡ | 1.00 (ref) | 1.19 (0.64–2.19) | 0.84 (0.44–1.60) | 1.04 (0.56–1.96) | 1.15 (0.61–2.16) | 1.00 (0.81–1.24) | 0.97 |
| MESA | |||||||
| Median (range)* | 4.5 (1.2–5.4) | 6.3 (5.5–7.1) | 8.2 (7.2–9.4) | 10.8 (9.5–12.7) | 16.3 (12.8–124.8) | — | — |
| Cases/N | 20/375 | 38/395 | 51/388 | 77/379 | 79/386 | — | — |
| Model 1† | 1.00 (ref) | 1.92 (1.08–3.39) | 2.59 (1.49–4.48) | 4.42 (2.60–7.52) | 4.22 (2.47–7.19) | 1.75 (1.45–2.10) | <0.0001 |
| Model 2‡ | 1.00 (ref) | 1.59 (0.89–2.85) | 1.90 (1.08–3.35) | 2.83 (1.62–4.95) | 2.14 (1.19–3.84) | 1.26 (1.01–1.56) | 0.03 |
| Pooled analysis§ | |||||||
| Median (range)* | 2.5 (0.2–3.6) | 4.6 (3.7–5.5) | 6.4 (5.5–7.4) | 8.8 (7.4–10.9) | 14.9 (10.9–139.1) | — | — |
| Cases/N | 62/1862 | 98/1852 | 124/1864 | 206/1851 | 300/1854 | — | — |
| Model 1† | 1.00 (ref) | 1.36 (0.98–1.89) | 1.56 (1.13–2.14) | 2.51 (1.86–3.40) | 3.59 (2.67–4.82) | 1.50 (1.39–1.63) | <0.0001 |
| Model 2‡ | 1.00 (ref) | 1.21 (0.87–1.69) | 1.21 (0.88–1.68) | 1.66 (1.22–2.27) | 1.70 (1.24–2.35) | 1.14 (1.04–1.24) | 0.005 |
| Model 3ǁ | 1.00 (ref) | 1.09 (0.71–1.66) | 1.40 (0.94–2.08) | 1.92 (1.30–2.82) | 1.66 (1.11–2.47) | 1.15 (1.02–1.30) | 0.02 |
Definition of abbreviations: HPFS = Health Professionals Follow-up Study; MESA = Multi-Ethnic Study of Atherosclerosis; NHS = Nurses’ Health Study; NHSII = Nurses’ Health Study II; ref = reference.
Fasting insulin values were reported as μU/ml.
Model 1: Adjusted for cohort (pooled analysis), age, race and ethnicity, sex (MESA and pooled analysis), menopausal status in women, smoking, sleep duration, diet quality, physical activity, hypertension, and family history of diabetes.
Model 2: Model 1 + continuous body mass index and waist circumference.
Based on the association estimates per doubling of fasting insulin, there was significant between-cohort heterogeneity in Model 1 (P = 0.01) and no significant between-study heterogeneity in Model 2 (P = 0.52).
Model 3: Model 2 + HbA1c.