Relationship between serum alkaline phosphatase level, C-reactive protein and leukocyte counts in adults aged 60 years or older

Serum alkaline phosphatase (ALP), a useful marker of hepatobiliary or bone disorders, has been known to be associated with cardiovascular disease (CVD), which is increasingly being viewed as an inflammatory disease. C-reactive protein level and leukocyte count have also been highlighted as independent risk markers of CVD. Thus, the mechanism underlying the link between elevated ALP and CVD could be subclinical low-grade inflammation. This study aimed to examine associations of serum ALP level with inflammatory markers. This cross-sectional study included 2403 participants (1324 men and 1079 women) aged ≥60 years who participated in a health examination program. Serum ALP quartiles were categorized as follows: Q1: ≤51, Q2: 52–61, Q3: 62–74 and Q4: ≥75 U/L. The odds ratios (ORs) and 95% confidence intervals (CIs) for high CRP and leukocyte count (≥75th percentiles) were calculated after adjusting for confounding variables across serum ALP quartiles using multiple logistic regression analysis. Median CRP level and mean leukocyte count increased in accordance with serum ALP quartiles. Compared to the lowest quartile, the ORs (95% CI) of the highest quartile for high CRP and leukocyte count were 2.03 (1.50–2.76) and 1.54 (1.13–2.10) after adjusting for age, sex, body mass index, smoking status, alcohol intake, fasting plasma glucose, log-transformed triglyceride and HDL-cholesterol levels. Serum ALP level was positively and independently associated with inflammatory markers in adults aged 60 years or older.