Study On The Correlation Between Body Weight And Tongue Image

1 ObjectiveUsing control study methods to discuss the differences of tongue between normal weight people and abnormal weight people, and to find the correlation between body mass index (BMI) and tongue characteristics. The method of color science was used to obtained tongue chromatic values of people in different weight for analysis in the difference of the tongue objectively. Then combining tongue characteristics with symptom, the ground for health management and preventive treatment of disease in Traditional Chinese Medicine (TCM) may be provided by tongue diagnosis.2 MethodsIn this study, the research plan was designed the principles of clinical epidemiology, using control study, with the checkup people as object. Following the clinical research plan, BMI was calculated. Meanwhile, each participant’s tongue had been examined and had its own digital tongue photo taken. Then analyzed the photos and got the chromatic values with method of color science. Using Classification and Determination of Constitution in TCM, physical identification was done and symptoms were record.To chose suitable statistics methods according to the data type (t-test, chi-square test, nonparametric test and logistic regression), and find the last result.3 Results3.1 The Distribution of BMIAmong the 1655 participants, there were 843 cases in normal weight group (43.74%), 724 cases in overweight or obese group (50.94%),88 cases in low weight group.3.2 The Correlation between BMI and Tongue CharacteristicsIn all participants, tongue characteristics were different in different groups of weight. Comparing with normal weight group, the overweight or obese cases had more dark red tongue, purple tongue, dark purple tongue, yellow tongue fur, gray and black tongue fur, thick and greasy tongue fur, and less pink tongue, shedding/little tongue fur(P<0.01 or P<0.05). Among the low weight cases, the incidence of red/crimson tongue, dot tongue, thing white tongue fur increased, while the occurrence of pink tongue reduced(P<0.01 or P<0.05). According to the result of logistic regression, positive correlation existed between dark red tongue, purple tongue, dark purple tongue, yellow tongue fur, gray and black tongue fur, thick and greasy tongue fur and BMI, and negative correlation existed between pink tongue, red/crimson tongue, dot tongue, thing white tongue fur, white tongue and BMI.3.3 Analysis of Chromatic Value in Different Groups of WeightIn different groups of weight, the value of b and h were different(P<0.01). Comparing lingual color information of macroscopic observation with chromatic value, in normal weight group, the value of L in the purple tongue, the value of a and C in the dark purple tongue and the value of b and h in the light white tongue were the highest. In the overweight or obese cases, the value of L, b and h in the light white tongue and the value of a and C in the red/ crimson tongue were the highest. In the low weight cases, the chromatic value in all kinds of lingual color showed no difference. The average color difference of each two kinds of lingual color was less than 5.3.4 The Correlation between Symptom and Tongue Characteristics in Different Groups of WeightRegression analysis showed that in normal weight group, positive correlation existed between pink tongue, normal shape tongue and "hands or feet feel cold or clammy", "feel feeble when talking", "sigh for no reason", "throat feel strange". In overwight or obese cases, positive correlation existed between thick tongue fur, yellow tongue fur and "catch colds more easily than others", "stomach/belly flabby", and negative correlation existed between teeth-marked tongue, thick and greasy tongue fur and "body feel heavy or lethargic", "have upper eyelid swelling", "have bitterness or a strange taste in mouth". In low weight cases, negative correlation existed between thick tongue fur, yellow tongue fur, white fur and "nose or face feel greasy, oily, or shiny", "have upper eyelid swelling", while negative correlation also existed between dot tongue and "feel cold easily in your abdomen, back, lower back or knees". 4 Conclusions 4.1 BMI and tongue characteristics showed corresponding relation.In the aspect of color, the tongue characteristic of normal weight people was pink. The tongue characteristic of overweight or obese people was dark red tongue, and tongue characteristic of low weight people was red/crimson tongue. In the aspect of fur, no matter how the weight of people changed, the tongue characteristic yellow thick tongue. The shape of tongue was always normal while BMI changed. In addition, tooth-mark tongue was numerously distributed. But tooth-mark tongue had little pathological significance. The shape of tongue showed low sensitivity to abnormal weight changes.4.2 Chromatic Values of the same lingual color in different groups of weight were different.Lightness in normal weight group was the hightest, and lightness in low weight group was the lowest. Lingual color in low weight group had the highest value of a, b, saturation and hue. Lingual color in overweight or obese group had the lowest value of b, saturation and hue. These differences of lingual color were difficult to identify by eyes. Thus, through the method of color science, the lingual color in different groups of weight can be compared in the micro level, and the subtle differences can be found.4.3 Tongue characteristics in different groups of weight were related to symptoms of physical identification in TCM.Normal weight cases had a stronger ability of self adjusting than others. But they were in a state of sub-health and had a tendency to state of phlegm-dampness. Overweight or obese cases had a lower tendency to state of yang deficiency. Due to the heat conversion of the dampness stagnancy, they were in stress state easily. Low weight cases showed a tendency to state of fire-heat.