The association between daily physical activity and plasma B-type natriuretic peptide in patients with glucose intolerance: a cross-sectional study

Abstract

Objectives: In spite of accumulating evidences suggesting an inverse association between insulin resistance and plasma B-type natriuretic peptide (BNP) levels, the effect of daily physical activity on plasma BNP in individuals with glucose intolerance remains unknown. We investigated the association of physical activity level (PAL) with plasma BNP in patients with impaired fasting glucose, impaired glucose tolerance and type 2 diabetes.

Design: Cross-sectional study.

Setting: Outpatients visiting the National Center for Global Health and Medicine Kohnodai Hospital.

Participants: A total of 60 patients with glucose intolerance who did not take any hypoglycaemic agents, cholesterol-lowering agents and antihypertensive agents were recruited. Patients who were diagnosed as having heart failure and renal impairment, engaged in sports-like exercise and resistance training were excluded.

Primary outcome measures: PAL was objectively measured by a triaxial accelerometer. The association between PAL and plasma BNP levels was assessed by multiple regression analysis.

Results: PAL was positively correlated with plasma BNP levels (r=0.296, p=0.021). PAL was still significantly correlated with plasma BNP levels after adjustment for age (β=0.290, p=0.014), and adjustment for age and body mass index (β=0.282, p=0.018). Plasma BNP levels were inversely correlated with serum insulin levels (r=-0.350, p=0.006) and homeostasis model assessment-estimated insulin resistance (HOMA-IR; r=-0.363, p=0.004). Serum insulin levels (mean±SD, 8.1±6.4 μU/mL) and HOMA-IR (2.4±1.9) in the high-BNP group were significantly lower than those (11.2±7.4 μU/mL and 3.7±3.0, respectively) in the low-BNP group.

Conclusions: Our findings propose the possibility that plasma BNP may be increased by daily physical activity and BNP is associated with insulin resistance.

Keywords: DIABETES & ENDOCRINOLOGY; PUBLIC HEALTH; SPORTS MEDICINE.

Figure 1

Correlation of physical activity level and plasma BNP levels in 60 participants. r Indicates the correlation coefficient analysed by Spearman's rank correlation coefficient.

Figure 2

Serum insulin levels (A) and the homeostatic model assessment-estimated insulin resistance (HOMA-IR) (B) in the high-BNP group (n=30) and the low-BNP group (n=30). Data are mean values±SD. We divided participants into the high-BNP group (≧8.0 pg/mL) and the low-BNP group (<8.0 pg/mL) by the median values of BNP. Differences in serum insulin levels and HOMA-IR between the high-BNP group and the low-BNP group were analysed by the Mann-Whitney U test.

Figure 3

Serum insulin levels (A) and homeostatic model assessment-estimated insulin resistance (HOMA-IR) (B) in each plasma BNP quartiles. Q1 is the lowest quartile and Q4 is the highest quartile. Boxes indicate medians and quartiles; whiskers indicate the lowest and highest values. We found a significant influence of plasma BNP on both serum insulin (p=0.018 by the Kruskal-Wallis ANOVA) and HOMA-IR (p=0.018). The difference between Q1 and Q2–4 was statistically analysed by Scheffe's F Test.