ABSTRACT
Objective To study the concentration distribution of acetone in fasting exhaled breath in diabetic patients and healthy subjects,to explore the effect of individual indexes on the concentration of acetone in fasting exhaled breath,and to study the role of individual indexes of fasting exhaled breath acetone in diabetes screening.Methods The acetone concentration measurements of fasting exhaled breath were performed on 265 healthy subjects,39 patients with type 1 diabetes (T1D),and 300 patients with type 2 diabetes (T2D) using real-time online respiratory acetone analyzer based on cavity ring-down spectroscopy (CRDS).SPSS 19.0 software was used to eliminate outliers,and relevant statistical analysis was carried out with the corresponding gender,age,height,body mass,body mass index (BMI) and blood glucose concentration (BGL).The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of fasting breath acetone concentration for diabetes diagnosing.Results The mean fasting breath acetone concentration in T1D patients was (2.24±1.43)×10-6 was significantly higher than (1.43±0.55)×10-6 in healthy subjects and (1.41±0.73)×10-6 in T2D patients,and the differences were statistically significant (all P＜0.05).The average fasting breath acetone concentration in male diabetic patients was higher than that in female patients.The mean fasting breath acetone concentration was positively correlated with age (R=0.31,P＜0.01) in healthy subjects,was positively correlated with BMI (R=0.33,P＜0.05) in T1D patients,and was positively correlated with height (R=0.18,P＜0.01) in T2D patients.The area under the ROC curve for the diagnosis of T1D by fasting breath acetone concentration was 0.853 with a sensitivity of 71.9％ and specificity of 87.4％ (P＜0.01),and for the diagnosis of T2D was 0.528 with a sensitivity of 54.1％ and specificity of 55.0％ (P＞0.05).Conclusions The detection of fasting breath acetone concentration is meaningful for T1D diagnosing,but has a low accuracy for T2D diagnosing (no statistically significant).
ABSTRACT
Objective To conduct breath test with a relatively large number of subjects for new data regarding breath acetone in diabetes using a high accuracy and high data throughput breath acetone analyzer based on the cavity ringdown spectroscopy (CRDS) technique.Methods The CRDS breath analyzer was validated by standard acetone gas samples with various concentrations and golden standard gas chromatography-mass spectrometry (GC-MS).A total of 917 breath samples from 260 type 2 diabetic (T2D) patients and 30 healthy individuals were collected under each of 4 different conditions: fasting, 2 h post-breakfast, 2 h post-lunch, and 2 h post-dinner, and the samples were tested by the breath analyzer.Results The linear fitting curve of standard acetone samples with various concentration had good linearity (R=1, P＜0.05).The linear fitting of the results of GC-MS and CRDS was 0.98, suggesting that the obtained acetone concentrations using both methods were consistent.For the 260 T2D subjects, the exhaled breath acetone concentrations ranged from 0.0 to 10.6×10-6, while for the 30 healthy subjects, the breath acetone concentration ranged from 0.1 × 10-6 to 2.0× 10-6.The mean breath acetone concentration of the 260 T2D subjects was (1.5±1.l)× 10-6, which was 1.4 times of(1.1±0.5)×10-6 for the 30 healthy subjects.The mean breath acetone concentrations under the 4 conditions for the 260 T2D subjects ((1.6±1.2)×10-6, (1.4±1.0)×10-6~, (1.4±0.9)×10-6, and (1.4±1.2)× 10-6) were higher than that of the 30 healthy subjects ((1.3±0.3)×10-6, (1.0±0.6)×10-6, (1.0±0.6)×10-6, and (1.1±0.4)×10-6), respectively.No correlation was found between the breath acetone concentration and the blood glucose level of the T2D subjects and the healthy individuals.Conclusions The GC-MS validation confirms that the CRDS breath acetone analyzer is a reliable instrument for fast response and on-line breath acetone measurement.An elevated mean breath acetone concentration exists in T2D subjects.The relationship between breath acetone level and physiological parameters needs to be further investigated.