Prevalence and Risk Factors of Monoclonal Proteinemia in Thai Population.

Monoclonal gammopathy of undetermined significance (MGUS) is associated with progression to multiple myeloma and related hematologic malignancies at the rate of 1% per year in western population. Reliable information on prevalence, risk factors and natural history of MGUS in general population are necessary for designing an early detection strategy for myeloma in Thailand.

The study was performed in subjects, 50 years of age or older, in Bangkok, one nearby province and 2 remote provinces of Thailand. The demographic data and suspected risk factor history were collected by questionnaires. Complete blood count as well as blood chemistry were done to exclude underlying hematologic and/or systemic conditions. Serum monoclonal proteins were detected using high-resolution gel electrophoresis.

Serum samples were obtained from 3,261 participants. There were 1,105 males (33.9%) and 2,156 females (66.1%). The median age was 57. Abnormal protein electrophoresis findings were detected in 76 samples (prevalence 2.3%, 95% confidence interval [CI] 1.8% - 2.8%) showing small M-spikes at gamma-globulin region in 50 (1.5%) or at beta-globulin region in 25 (0.8%) or hypogammaglobulinemia in 1 case (0.03%). The prevalence of MGUS in subjects less than 60, 60-69 and 70 yrs or more was 2.0% (41/1975), 2.6% (22/851) and 3.0% (13/435), respectively. Using multivariate analysis, presence of MGUS was strongly associated with history of drug abuse (odd ratio 4.63, 95%CI 1.14-22.08) and current residences outside Bangkok (odd ratio 2.30, 95%CI 1.18-4.79). Radiation and chemical exposure, hair and nail-coloring products and pesticides were not statistically significant risk factors in our population.

The overall prevalence of MGUS in Thai population was 2.3%, lower than those of western countries but comparable to what reported from Japan and Taiwan.

No relevant conflicts of interest to declare.