A Nonlinear Relation between Body Mass Index and Long-Term Poststroke Functional Outcome-The Importance of Insulin Resistance, Inflammation, and Insulin-like Growth Factor-Binding Protein-1.

Both high serum insulin-like growth factor-binding protein-1 (s-IGFBP-1) and insulin resistance (IR) are associated with poor functional outcome poststroke, whereas overweight body mass index (BMI; 25-30) is related to fewer deaths and favorable functional outcome in a phenomenon labeled "the obesity paradox". Furthermore, IGFBP-1 is inversely related to BMI, in contrast to the linear relation between IR and BMI. Here, we investigated s-IGFBP-1 and IR concerning BMI and 7-year poststroke functional outcome. We included 451 stroke patients from the Sahlgrenska Study on Ischemic Stroke (SAHLSIS) with baseline measurements of s-IGFBP1, homeostasis model assessment of IR (HOMA-IR), BMI (categories: normal-weight (8.5-25), overweight (25-30), and obesity (>30)), and high-sensitivity C-reactive protein (hs-CRP) as a measure of general inflammation. Associations with poor functional outcome (modified Rankin scale [mRS] score: 3-6) after 7 years were evaluated using multivariable binary logistic regression, with overweight as reference due to the nonlinear relationship. Both normal-weight (odds-ratio [OR] 2.32, 95% confidence interval [CI] 1.30-4.14) and obese (OR 2.25, 95% CI 1.08-4.71) patients had an increased risk of poor functional outcome, driven by deaths only in the normal-weight. In normal-weight, s-IGFBP-1 modestly attenuated (8.3%) this association. In the obese, the association was instead attenuated by HOMA-IR (22.4%) and hs-CRP (10.4%). Thus, a nonlinear relation between BMI and poor 7-year functional outcome was differently attenuated in the normal-weight and the obese.

Serum IGFBP-1 Concentration as a Predictor of Outcome after Ischemic Stroke-A Prospective Observational Study.

Insulin-like growth factor-binding protein-1 (IGFBP-1) regulates insulin-like growth factor-I (IGF-I) bioactivity, and is a central player in normal growth, metabolism, and stroke recovery. However, the role of serum IGFBP-1 (s-IGFBP-1) after ischemic stroke is unclear. We determined whether s-IGFBP-1 is predictive of poststroke outcome. The study population comprised patients (n = 470) and controls (n = 471) from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Functional outcome was evaluated after 3 months, 2, and 7 years using the modified Rankin Scale (mRS). Survival was followed for a minimum of 7 years or until death. S-IGFBP-1 was increased after 3 months (p < 0.01), but not in the acute phase after stroke, compared with the controls. Higher acute s-IGFBP-1 was associated with poor functional outcome (mRS score > 2) after 7 years [fully adjusted odds ratio (OR) per log increase 2.9, 95% confidence interval (CI): 1.4-5.9]. Moreover, higher s-IGFBP-1 after 3 months was associated with a risk of poor functional outcome after 2 and 7 years (fully adjusted: OR 3.4, 95% CI: 1.4-8.5 and OR 5.7, 95% CI: 2.5-12.8, respectively) and with increased mortality risk (fully adjusted: HR 2.0, 95% CI: 1.1-3.7). Thus, high acute s-IGFBP-1 was only associated with poor functional outcome after 7 years, whereas s-IGFBP-1 after 3 months was an independent predictor of poor long-term functional outcome and poststroke mortality.

Relationship between Levels of Pre-Stroke Physical Activity and Post-Stroke Serum Insulin-Like Growth Factor I.

Physical activity (PA) and insulin-like growth factor I (IGF-I) have beneficial effects for patients who have suffered an ischemic stroke (stroke). However, the relationship between the levels of PA and IGF-I after stroke has not been explored in detail. We investigated the pre-stroke PA level in relation to the post-stroke serum IGF-I (s-IGF-I) level, at baseline and at 3 months after the index stroke, and calculated the change that occurred between these two time-points (ΔIGF-I). Patients (N = 380; 63.4% males; mean age, 54.7 years) with data on 1-year leisure-time pre-stroke PA and post-stroke s-IGF-I levels were included from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS). Pre-stroke, leisure-time PA was self-reported as PA1-4, with PA1 representing sedentary and PA2-4 indicating progressively higher PA levels. Associations between s-IGF-I and PA were evaluated by multiple linear regressions with PA1 as the reference and adjustments being made for sex, age, history of previous stroke or myocardial infarctions, cardiovascular risk factors, and stroke severity. PA correlated with baseline s-IGF-I and ΔIGF-I, but not with the 3-month s-IGF-I. In the linear regressions, there were corresponding associations that remained as a tendency (baseline s-IGF-I, p = 0.06) or as a significant effect (ΔIGF-I, p = 0.03) after all the adjustments. Specifically, for each unit of PA, ΔIGF-I increased by 9.7 (95% CI 1,1-18.4) ng/mL after full adjustment. This supports the notion that pre-stroke PA is independently related to ΔIGF-I.