Association between serum leptin concentration and white blood cell count in middle-aged Japanese men and women.
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.
Mabuchi
Tomoko
T
Department of Public Health/Health Information Dynamics, Field of Social Life Science, Nagoya University Graduate School of Medicine, Japan.
Yatsuya
Hiroshi
H
Tamakoshi
Koji
K
Otsuka
Rei
R
Nagasawa
Nobue
N
Zhang
Huiming
H
Murata
Chiyoe
C
Wada
Keiko
K
Ishikawa
Miyuki
M
Hori
Yoko
Y
Kondo
Takaaki
T
Hashimoto
Shuji
S
Toyoshima
Hideaki
H
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
D020738:Leptin