title: Association between serum leptin concentration and white blood cell count in middle-aged Japanese men and women.
abstract: BACKGROUND
  Leptin's hematopoietic or proinflammatory role has been experimentally reported. We investigated whether serum leptin concentrations are associated with white blood cell (WBC) counts in humans.
  
  
  METHODS
  Serum leptin concentrations of Japanese civil servants aged 40 to 59 years (1082 men and 200 women) were analyzed in relation to their WBC count. Serum leptin concentrations and WBC counts were measured by radioimmunoassay and automated particle counter respectively, using samples obtained at the time of the participants' annual health checkups.
  
  
  RESULTS
  The geometric mean (+/-geometric standard deviation) leptin concentrations were 3.25 +/- 1.82 ng/mL and 6.25 +/- 3.99 ng/mL, and the geometric mean WBC counts, 5770 +/- 1269/mm(3) and 5107 +/- 1228/mm(3), in men and women respectively. The WBC count adjusted for age, body mass index (BMI), physical activity, and drinking and smoking habits increased together with the increase in leptin concentration. Multiple linear regression against WBC count by the leptin concentration and those covariates revealed a significant and independent association with serum leptin concentration especially in women (standardized beta = 0.31, p < 0.001), and also in men (standardized beta = 0.17, p < 0.001). BMI was not significantly associated with WBC counts in the multivariate model adjusting for leptin levels in both sexes.
  
  
  CONCLUSIONS
  Our results are in line with leptin's hematopoietic or proinflammatory functions. The increased WBC counts often observed in obese people would be mediated by the increased leptin concentration.
authors.affiliation: Department of Public Health/Health Information Dynamics, Field of Social Life Science, Nagoya University Graduate School of Medicine, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Mabuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yatsuya
authors.forename: Koji
authors.initials: K
authors.lastname: Tamakoshi
authors.forename: Rei
authors.initials: R
authors.lastname: Otsuka
authors.forename: Nobue
authors.initials: N
authors.lastname: Nagasawa
authors.forename: Huiming
authors.initials: H
authors.lastname: Zhang
authors.forename: Chiyoe
authors.initials: C
authors.lastname: Murata
authors.forename: Keiko
authors.initials: K
authors.lastname: Wada
authors.forename: Miyuki
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Hori
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kondo
authors.forename: Shuji
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Hideaki
authors.initials: H
authors.lastname: Toyoshima
mesh_terms: D000328:Adult; D000428:Alcohol Drinking; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D006410:Hematopoiesis; D006801:Humans; D007249:Inflammation; D007564:Japan; D020738:Leptin / Q000097:blood* / Q000502:physiology; D007958:Leukocyte Count; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012907:Smoking
chemical_list: D020738:Leptin