The Impact Of Body Mass Index On Health-related Quality Of Life

Objective:Body mass index(BMI)is an indicator that reflects the relationship between weight and height of the adult and determines the degree of obesity.In China,BMI<18.5 is considered to be underweight,18.50≤BMI<24.0 is considered to be normal,24.0<BMI<28.0 is overweight and BM≥28.0 is obese.In practice,researches on the underweight are relatively few,because underweight people are far less to the people of overweight and obese.It becomes the focus of the scholars’ research because of the prevalence of obesity and the rapid growth rate.Most people believe that overweight and obesity are the risk factors for many diseases and will increase the risk of death.However,there are different views on the impact of overweight and obesity on health-related quality of life,including both negative and positive.Therefore,the author believes that there are other factors influencing the relationship between the BMI and HRQOL.Studies at home and abroad have shown that physical inactivity can cause severe diseases.The general population’s health-related quality of life also decreases with the decrease of exercise level.And the level of exercise also has a great influence on mental health.Therefore,this study will include sports factors into the study of obesity and health.The effect of BMI on health-related quality of life will be studied in the different exercise levels by analyzing the data from previous surveys conducted from the research team of the author.It will provide a theoretical basis for people to correctly understand overweight and obesity and manage weight and references for scientific guidance campaigns.Finally,it can promote people’s physical and mental health and improve their health level.Methods:The 3353 objects of the research come from the database of the people in health examination from the survey of our team.The main research contents of objects include:general information(gender,age,marital status,educational level,weight,height),daily habits(exercise habits,smoking,drinking,salty,sweet),chronic diseases,and SF-36.BMI is calculated by height and weight.BMI<18.5 is underweight,18.5≤BMI<24.0 is normal,24.0<BMI<28.0 is overweight and BM≥28.0 is obese.HRQOL was measured by sf-36.To obtain the score of Physical Component Summary(PCS)and its four dimensions of Physical Functioning(PF),Role Physical(RP),Bodily Pain(BP),General Health(GH),as well as the Mental Component Summary(MCS)and its four dimensions of Vitality(VT),Social Functioning(SF),Role Emotional(RE),Mental Health(MH).Statistical analysis:① using analysis of variance to analyze the differences of HRQOL of different BMI or exercise-level groups.Further,the exercise levels and BMI were classified as group variables and independent variables,analyzes the difference of HRQOL between different groups,and using LSD method to analyze the difference in each group.②The influence of BMI,personal basic information,living habits and chronic diseases on HRQOL was analyzed by multiple logistic regression grouped by exercise level.③The regulating effect of exercise level on BMI and HRQOL was analyzed by the grouping linear regression.Statistical analysis was completed using SPSS 17,and P<0.05 was considered statistically significant.Results:Among the 3,353 subjects,1,409 were males,accounting for 42.02%,and 57.98%were females of1944.The average age is 43.47.1.HRQOL of different BMI groups:①In the field of physical,except the dimension of PF,the HRQOL of overweight people was higher,the underweight people scored higher in PF dimension.There was statistically significant difference in HRQOL physiology between BMI groups(P<0.05).②In the field of psychology,in addition to the SF dimension,HRQOL increased with the increase of obesity level in VT,RE,MH and MCS dimensions.Moreover,HRQOL in the overweight and obese groups was significantly higher than that in the normal-weight and underweight groups(P<0.05).2.HRQOL of different exercise levels:①In the field of physiology,those who exercise sometimes scored higher in PF,RP,BP and PCS,except for the GH dimension.However,the difference in HRQOL scores was small.②In the field of psychology,the scores of HRQOL of each dimension increase with the increase of exercise level.In particular,the scores of MCS and its VT and MH dimensions were significantly higher in regular exercise group than the other two groups(P<0.05).3.HRQOL in different BMI groups stratified by the levels of exercise:①When you exercise regularly,there was no significant difference in physical field among different BMI groups.There was a significant difference in psychology field among different BMI categories(P<0.05).HRQOL was significantly better in overweight or obese people than in underweight or normal groups(P<0.05).②When you exercise sometimes,the scores of physical field and psychology field of overweight group were higher,except the PF dimension.(P<0.05).③When there was nearly no exercise,HRQOL scores increased with the increase of obesity levels,the obese group scored higher.In particular,the differences in psychological were significant(P<0.05).4.HRQOL in different exercise levels classified by BMI:①Underweight people only showed significant difference between different levels of exercise in the PF dimension(P<0.05).People who exercise regularly tend to be significantly better than those who exercise sometimes or do not exercise at all.② The HRQOL of the normal people significantly increased with the increase of exercise level in VT and MH dimensions(P<0.05).③With the decrease of exercise level,HRQOL of overweight people also decreased significantly(P<0.05),except the PF and BP dimension.④Only in the MH dimension,obese people showed that HRQOL in the higher exercise level was significantly higher than that in the group of people who exercise sometimes or scarcely(P<0.05).5.Logistic regression analysis of the effect of BMI on HRQOL between the different exercise levels:Taking the normal weight group as the reference,the physical field:①In the regular exercise group,overweight is a statistically significant protective factor for physical field(OR=0.57,95%CI =0.38,0.84)and its PF dimension(OR=0.66,95%CI=0.44,0,97),RP dimension(OR=0.63,95%CI =0.42,0.95),BP dimension(OR=0.64,95%CI=0.44,0.92);Obesity is a statistically significant protective factor for RP dimension(OR=0.53,95%CI=0.29,0.98)and GH dimension(OR=0.56,95%CI=0.32,0.92).Underweight had no significant effect on HRQOL.②In the group of exercise sometimes,overweight is a statistically significant protective factor for physical field(OR=0.54,95%CI=0.39,0.74)and its RP dimension(OR=0.65,95%CI=0.46,0.92),BP dimension(OR=0.71,95%CI=0.53,0.97),GH dimension(OR=0.58,95%CI=0.43,0.78).Obesity is only a significant protective factor for the physical field(OR=0.53,95%CI=0.33,0.85).Underweight will aggravate the physiological impairment of HRQOL.However,the effect is significant only in the BP dimension(OR=1.93,95%CI=1.00,3.70).③ In the group of seldom exercise,overweight is a significant protective factor for the physical field(OR=0.75,95%CI=0.59,0.96)and its GH dimension(OR=0.71,95%CI=0.56,0.89).Obesity is a protective factor for physical field(OR=0.71,95%CI=0.52,0.98).Underweight may aggravate the physiological impairment of HRQOL,but it is not statistically significant.The psychological aspects:①In the regular exercise group,overweight is the protective factor for MCS(OR=0.63,95%CI=0.42,0.93)and its VT dimension(OR=0.68,95%CI =0.47,0.99),SF dimension(OR=0.59,95%CI=0.38,0.90),RE dimension(OR=0.59,95%CI=0.39,0,90)and MH dimension(OR=0.58,95%CI=0.40,0.86).Obesity is a statistically significant protective factor for MCS(OR=0.56,95%CI=0.32,0.98),its RE dimension(OR=0.53,95%CI=0.29,0.96)and MH dimension(OR=0.44,95%CI=0.24,0.78).Underweight has no significant effect on HRQOL psychology impairment.②In the group of exercise sometimes,overweight is the protective factor for MCS(OR=0.52,95%CI=0.38,0.70)and its VT dimension(OR=0.61,95%CI=0.45,0.82),SF dimension(OR=0.59,95%CI =0.42,0.84),RE dimension(OR=0.52,95%CI=0.37,0.71)and MH dimension(OR=0.49,95%CI=0.36,0.66);obesity has statistical significance in the psychological field of the VT dimension(OR=0.56,95%CI =0.36,0.87)and MH dimension(OR=0.62,95%CI=0.40,0.95).The effect of underweight on HRQOL psychology is not signifcant.③In the group of seldom exercise,overweight has statistical significance on MCS(OR=0.76,95%CI=0.60,0.95),its VT dimension(OR=0.71,95%CI=0.57,0.89)and MH dimension(OR=0.64,95%CI=0.51,0.81).Obesity is significant protective factor for MCS(OR=0.57,95%CI=0.42,0.79)and its VT dimension(OR=0.56,95%CI=0.41,0.77),RE dimension(OR=0.58,95%CI=0.41,0.82)and MH dimension(OR=0.63,95%CI=0.46,0.86).The effect of underweight on HRQOL psychology is not obvious.6.The regulation effect of exercise level between BMI and HRQOL:There is a moderating effect in the exercise levels between BMI and PCS and its associated RP,BP and GH dimensions,MCS and its associated VT,SF,RE and MH dimensions(except PF dimension)by the linear regression of BMI to HRQOL grouped by exercise level.Conclusion:The relationship between BMI and HRQOL is affected by different exercise levels.In the group of exercise always and sometimes,HRQOL of overweight is better than the underweight and normal-weight people.And overweight is the protective factor for the physical field and psychology field.In the group of exercise scarcely,HRQOL of obese people is better than the other groups.And obese is a protective factor for psychology field.The HRQOL of underweight people is always relatively poor.Except PF dimension,the exercise level has the regulating effect between BMI and HRQOL.