Underweight diabetic patients in Singapore have increased risk of TB
Nested in the long-running Singapore Chinese Health Study, a new study by researchers in Singapore, based on data from over 60,000 middle-aged to older adults, has found that people who suffer from diabetes and who are also underweight have a much higher risk of active tuberculosis (TB) than their heavier counterparts, supporting calls for TB screening among these patients.
SINGAPORE – “’Persistent cough in underweight
patients with diabetes warrants screening for active
tuberculosis.” This is the message in the editorial of the
December 2019 issue of the
International Journal of Tuberculosis and Lung Disease, based on findings from a Singapore-based study that have
reported that patients with diabetes and who were also
underweight had an eight-fold increase in their risk of
contracting active TB, compared to obese individuals without
diabetes.
Health experts have established that
diabetes is a risk factor for active TB disease. Epidemiologic
studies have also shown that individuals with low body mass
index (BMI), especially those in the lean or underweight range,
have a higher risk of active TB compared to their heavier
counterparts. However, since increased BMI is a risk factor for
diabetes, most patients with diabetes tend to have high BMI in
Western populations. In contrast, in Asian populations, and also
in Singapore, a large proportion of patients with diabetes are
not overweight, but are lean or even underweight. Hence, it is
of public health importance to study the joint effect of
diabetes and BMI in modulating the risk of TB in Asian
populations, where diabetes develops at lower BMI.
Researchers
in Singapore, led by Koh Woon Puay, who is Professor at Duke-NUS
Medical School and the National University of Singapore’s
Saw Swee Hock School of Public Health, used data from the
population-based study, the Singapore Chinese Health Study, to
examine the combined association of diabetes and BMI with risk
of active TB disease.
Professor Koh, the
Principal Investigator of the Singapore Chinese Health Study,
explained, “The key finding in this study is that diabetes
and low BMI are independent risk factors for active TB disease.
Hence, patients with diabetes and who are also lean or
underweight have a substantially increased risk from the effects
of both factors.”
Dr Cynthia Chee, a
co-author of the study, commented, “Singapore’s TB
incidence rate of 35 to 40 per 100,000 population is 5–10
times that of the US, Australia and the UK. Diabetes is a major
problem in Singapore, affecting one in nine persons aged 18 to
69. In order to bring down our TB rate, it is important for all
physicians to have a heightened awareness of the link between
diabetes and TB, so as to facilitate the early diagnosis of
active TB in this important risk group.”
“The
National Tuberculosis Programme – also known as the
Singapore Tuberculosis Elimination Programme, or STEP –
welcomes the publication of this landmark study and is proud to
have played a part,” said Adjunct Associate Professor
Jeffery Cutter, Acting Director, National Tuberculosis
Programme, National Centre for Infectious Diseases.
Based
on this study, Professor Anthony Harries, who is a renowned
researcher in TB from the International Union Against
Tuberculosis and Lung Disease, called for physicians in diabetes
clinics to practice targeted screening with a focus on
underweight individuals, and for the conduct of trials to study
the value of targeted TB preventive therapy among underweight
patients with diabetes.
Reference: Soh, A.Z., Chee, C.B.E., Wang, Y.T., Yuan, J.M., and Koh, W.P. Diabetes and body mass index in relation to risk of active tuberculosis: a prospective population-based cohort. The International Journal of Tuberculosis and Lung Disease, Volume 23, Number 12, 1 December 2019, pp. 1277-1282(6). DOI: 10.5588/ijtld.19.0094
Source:
Duke-NUS Medical School
