Summary
The effects of biological variations on platelet counts were investigated in 694 healthy
subjects aged 18 to 60 years living in three cities including Chengdu (Sichuan Province),
Suzhou (Jiangsu Province) and Harbin (Heilongjang Province) in China. Platelet counts
in healthy subjects were significantly lower in Chengdu (52∼202 X 109/L) and Suzhou (60∼259 X 109/L) than in Harbin (154∼348 X 109/L)(p <0.0001), but the mean platelet volume (MPV) determined concurrently was negatively
correlated with platelet count, the MPV values were significantly higher in Chengdu
(11.8∼15.6 fl) and Suzhou (10.9∼15.8 fl) than in Harbin (9.5∼12.9 fl) (p < 0.0001). Platelet counts were significantly higher in summer (73∼289 X 109/L) than in winter (52∼202 X 109/L) (p <0.0001), but the MPV values were lower in summer (11.2∼14.7 fl) than in winter (11.8∼15.6
fl) (p <0.05) in Chengdu. Platelet associated immunoglobulin (PA-IgG) in Chengdu was revealed
to be significantly higher in the low platelet count group (<150 X 109/L, 13.5 ± 7.1 ng/107 PLT) than in the normal platelet count group (≥150 X 109/L, 8.3 ± 2.7 ng/107 PLT)(p <0.0001). Similar results were observed in Suzhou for the reticulated platelet ratio,
which was significantly higher in the low platelet count group (19.5 ± 7.1%) than
in the normal platelet count group (11.6 ± 2.7%)(p <0.01). The bleeding time in Chengdu showed a significantly longer time in the low
platelet count group (8.6 ± 2.3 min) than in the normal platelet count group (6.0
± 1.2 min)(p <0.01). With regard to the effects of lipids on platelet counts, the HDL values were
significantly higher in the normal platelet count group (1.60 ± 0.76 mmol/L) than
the low platelet count group (1.23 ± 0.31 mmol/L) (p <0.01); but no significant differences in cholesterol and triglycerides values between
the normal and low platelet count groups (p >0.05) were recorded. These findings suggest that the platelet counts could be greatly
influenced in healthy subjects by biological variations such as geographical, seasonal,
and lipid variations.
Keywords
Platelet count - healthy adults - biological variation - China