การศึกษาความชุกและปัจจัยเสี่ยงของผู้ป่วยที่มีเม็ดโลหิตขาวชนิดนิวโตรฟิลต่ำโดยที่ยังไม่มีอาการในประชากรไทย / ปณิสินี ลวสุต = The prevalence and etiology of asymptomatic neutropenia in Thai population / Panisinee Lawasut
Background The automated complete blood cell count is generally used, including in routine health checkups. With this screening, cases with low or borderline white blood cells count(WBC) without any symptoms are occasionally detected. These are problematic because there is no well-defined cutoff point of neutropenia for Thais. In addition, the risk factors that should be investigated remain unknown. Therefore, we conducted a community-based study to determine the prevalence and the preliminary etiologies of asymptomatic neutropenia in Thai population. Methods Blood specimens and medical personnel-assisted self-report questionnaires were collected from the population in Bangkok and 4 surrounding provinces. Neutropenic cases were those with absolute neutrophil count (ANC) < 1.5 x 109/l as used without ethnic determination. Reviewed of medical histories and laboratory tests to elucidate the risk factors of neutropenic cases were performed.
Results There were a total of 7,228 subjects, 2,685 males and 4,543 females from the age of 18-99 years (median 49.0). The WBC and ANC distribution was skewed to the right. The median WBC and ANC were 7.33 x 109/L (Q1-Q3 6.17-8.71) and 3.95 x 109/L (Q1-Q3 3.16-4.90), respectively. Thirty one of participants had neutropenia (0.43%, 95% CI 0.29-0.56). The prevalence for each sex was 0.26% (95% CI 0.07-0.44) in males and 0.52% (95% CI 0.31-0.72) in females. The risk factors found were medications (n=3, 2 from chemotherapy, 1 from Peginterferon/Ribavirin), chronic active hepatitis (n=5), thyroid disorders (n=4, hyperthyroidism 1, hypothyroid 3), rheumatoid arthritis (n=1) and malnutrition (n=2). The other abnormal laboratory findings were low serum ferritin in 6 cases, ANA positive in 4 cases and rheumatoid factor positive in 1 case. No anti-HIV positive case found. The risk factors were still cannot be established in at least 9 of cases. The only risk factor from history that associated with neutropenia is cancers, odd ratio 16.54 (95%CI 4.69-58.29). But if neutropenic cases from chemotherapy were excluded, there was no significant risk factor found. Conclusion The prevalence of asymptomatic neutropenia in Thai population was 0.43% (95% CI 0.29- 0.56), 0.26% (95% CI 0.07-0.44) in males and 0.52% (95% CI 0.31-0.72) in females. Around two third of cases had possible risk factors. Additional studies for the association of the risk factors and the causes of diseases need to be explored.
