The euglycemic hyperglycemic clamp is generally regarded as a reference method for assessing insulin sensitivity. However, this method is laborious and expensive. The oral glucose tolerance test (OGTT), the most commonly used method for evaluating whole body glucose tolerance, has often been used to assess insulin sensitivity. In the previous studies the correlation between the insulin sensitivity index (ISI) obtained from the OGTT (ISI(OGTT)) and those obtained from the glucose clamp (ISI(Clamp)) may not be satisfactory. This is because the glucose clamp study is designed for measuring peripheral glucose utilization, whereas plasma glucose responses during the OGTT are the results of peripheral glucose utilization and hepatic glucose production. Based on this problem, we developed a new equation, ISI(OGTT), [1.9/6 x body weight (kg) x fasting plasma glucose (mmol/liter) + 520 - 1.9/18 x body weight x area under the glucose curve (mmol/h.liter) - urinary glucose (mmol)/1.8] / [area under the insulin curve (pmol/h.liter) x body weight], which would represent peripheral glucose utilization only. We tested our equation with ISI(Clamp) and also compared with others. Thirty-three healthy volunteers (16 males) with normal glucose tolerance underwent a 75-g, 3-h OGTT on the morning of d 1 and a glucose clamp on the morning of d 2. Their mean (+/-SD) age and body mass index were 30.8 +/- 8.3 yr and 22.0 +/- 3.9 kg/m(2), respectively. The mean (+/-SD) glucose disposal rate and ISI determined by glucose clamp were 27.46 +/- 16.55 micro mol/kg.min and 7.39 +/- 2.72 micro mol/kg.min/pmol.liter, respectively. Pearson's correlation coefficient between our ISI(OGTT) and ISI(Clamp) was 0.869 (P < 0.0001) which was stronger than those corresponding values calculated from HOMA, QUICKI, Belfiore, Cederholm, Gutt, Matsuda, and Stumvoll, the respective values of which were 0.404, 0.434, 0.643, 0.533, 0.584, 0.734, and 0.508. In conclusion, the ISI(OGTT) derived from our equation is more suitable than others in assessing insulin sensitivity in subjects with normal glucose tolerance. Further studies in subjects with impaired glucose tolerance and diabetes mellitus should be performed to confirm the validity of this equation.

SUMMARY: Using the enumeration district (ED) block level this study looked at the incidence of dengue fever and dengue haemorrhagic fever (DF/DHF) within the Songkhla municipality in Thailand. Each of the 146 blocks in this area were considered as study units and surveyed for their environmental characteristics. A total of 287 cases of DH/DHF occurring in the year 1998 were selected for this study and the location of their homes mapped. Clustering analysis showed point clustering of the homes (P<0·0001) which was probably due to high density habitation, without any actual prevalence of case clustering. There was no evidence of clustering of the ED blocks with an incidence of DF/DHF (P=0·32). DF/DHF incidence for each block was strongly associated with the percentages of shop-houses, brick-made houses and houses with poor garbage disposal (all P<0·01). DF/DHF control should be emphasized for the areas which have a predominance of these housing types.

Background: Clinical manifestations of chikungunya (CHIK) are similar to those of dengue. It would be useful to be able to identify clinical manifestations that could reliably help to differentiate CHIK from dengue and other acute febrile illnesses during a CHIK outbreak in a dengue-endemic area. Methods: A prospective cohort study was conducted between April and July 2009 in children aged 1 month to 15 years who lived in a CHIK outbreak area in southern Thailand and who had fever <7 days with arthralgia/arthritis, myalgia or rash. CHIK was confirmed by real-time polymerase chain reaction or the indirect immunofluorescence test. Results: Fifty patients were suspected of having CHIK, of whom 32 were confirmed, 1 had coinfection with dengue viral infection (DVI), 10 had dengue alone and 7 had an acute febrile illness. The specificity and positive predictive value of fever and arthralgia together to diagnose CHIK were 47.1% and 74.2%, and the corresponding values of the standard clinical triad (fever, arthralgia, rash) were 70.6% and 83.3%, respectively. Fever ≤2 days, skin rash during fever and white blood cell count ≥ 5000 cells/mm³ were independently and significantly associated with CHIK in comparison with DVI and acute febrile illnesses, with relative risk ratios (95% confidence intervals) of 10.4 (0.9–116) and 13.7 (1.3–145), 13.8 (1.2–164) and 14.8 (1.6–168), and 18.3 (1.7–194) and 1.8 (0.1–20.6), respectively. Conclusions: During a CHIK outbreak in a DVI-endemic area, overdiagnosis of CHIK was common. Skin rash during fever and white blood cell count ≥ 5000 cells/mm³ or specific antigen testing (if available) can be helpful in differentiating CHIK from DVI.