Mukhyaprana MP,Vidyasagar S,Shashikiran U,Clinical Profile of Type2 Diabetes Mellitus and Body Mass Index- Is There any Correlation? Calicut Medical Journal 2004;2(4):e3.The Calicut Medical Journal

Prabhu Mukhyaprana M*,Sudha Vidyasagar **,Shashikiran U***,

*Asst Professor of Medicine,
**Professor, Department Of Medicine,
***Asst. Professor of Medicine,
Dr T.M.A Pai Hospital, Udipi, Kasthurba Medical College, Manipal,

Address For Correspondence
Dr.Prabhu Mukhyaprana M MD
Asst Professor of Medicine,
Dr T.M.A .Pai Hospital, Udupi,
Kasthurba Medical College, Manipal,
Karnataka 576119
email:mmukhyaprana@yahoo.com
Phone # 0820-2526503, Mobile-98452-48744

ABSTRACT
BACKGROUND: Obesity in Type 2 Diabetes is uncommon in Indian population, compared to western population. Markers of obesity are Body mass index (BMI) & waist Hip ratio (WHR). Does BMI by current definition will correlate well with diabetes related complications in Indian Diabetic population?

AIM: To study clinical profile and complications among four groups of cases of type 2 diabetes classified based on BMI Lean, Normal weight, Over-weight, and Obese Diabetics.

SETTING & DESIGN: Diabetes clinic Dr TMA Pay Hospital, Udupi attached to K M C Manipal.
Descriptive case series analysis of 500 serial type 2 diabetics

MATERIALS & METHODS: 500 Type 2 diabetic patients from Diabetic clinic between July 2000 to January 2001 divided into 4 groups based on body mass index (BMI) were our study subjects. Detailed clinical examination and screening for micro/macro vascular complications was done in all patients

RESULTS: Lean diabetics were 7.4%. Majority of diabetics had normal weight (65%). 24% belonged to overweight group; only2.6% of diabetics were obese. Incidence of hypertension in lean diabetic was 16.2%, whereas it was 38.8% in normal weight diabetics 42% in over weight diabetics and 61.5% in obese diabetics. The incidence of ischemic heart disease (I.H.D) was very low in lean diabetics (2.7%); it was 13.88% in normal weight diabetics, 12% in over weight diabetics and 23% in obese diabetics. As body mass increases, the prevalence of macro vascular complications was increasing. But micro vascular complications prevalence was similar in all groups. Fasting and postprandial sugar levels were significantly higher in lean diabetics. Lean diabetics had significantly favorable lipid profile compared to other groups.

CONCLUSIONS: Obesity as defined body mass index is uncommon in Indian context. However subtle signs of obesity like waist hip ratio are abnormal even in diabetics with normal and lean BMI. Lean diabetics like all other groups are prone for micro vascular complications, whereas over-weight and obese diabetics are prone for macro vascular complications like I.H.D. and hypertension. Lean diabetics have more severe hyperglycemia and favorable lipid profile compared to other groups.

KEY WORDS: BMI, Waist Hip Ratio, Lean Diabetics, and micro/macro vascular complications.

Introduction:
Diabetes is the most common metabolic disorder all over the world. The incidence of diabetes is showing an alarming rise in developing countries, particularly in India (1). Obesity is considered as part of syndrome X in pathogenesis of type 2 diabetes. 60-80% of the diabetics in developed countries are obese (2) whereas in India we find that clinical profile of diabetics is different (6,7,8,9.10)
Most patients attending our diabetic clinic are not obese as defined by existing parameters such as body mass index (BMI). It has been interesting to note that most patients fall in normal weight group and some even lean. Since obesity does contribute in a considerable way to complications of diabetes, we thought it would be worthwhile to study if BMI had any implication on the complications of diabetes. Since the drug of choice has been different in diabetic based on their BMI, redefinition of obesity may help in making these clinical decisions.
We have a diabetic clinic with significant number of lean type 2 diabetics. As there were no major published studies done in South Karnataka diabetic population we undertook a study to look whether variations in body weight affect the clinical presentation, co-morbid illnesses, and the incidence of complications in diabetic patients.

We studied 500 type2 diabetic patients from our Diabetic clinic, both outpatient and in-patient, between July 2000 and January 2001. Patient was diagnosed as type 2 diabetic based on American Diabetes Association 2000 (11). A detailed history was taken about the duration of diabetes, age of onset, family history and presence of complications. Height and weight were recorded in all cases. BMI was calculated based on formula weight (in kg) / height2 (in mt).

Patients were divided in to four groups based on the BMI as below:

<18.5 Lean Diabetics.
18.5-<25 Normal Weight Diabetics
25-<30 Over-weight Diabetics
>30 Obese Diabetics

Waist measurement was taken as abdominal circumference at midpoint between the costal margin and anterior superior iliac spine. Hip measurement taken as maximum diameter at the greater trochanter (3). Waist Hip Ratio (WHR) was calculated in each case. Waist Hip Ratio was considered abnormal, if >0.95 for males and >0.8 for females(3). Patients were clinically screened for micro vascular and macro vascular complications. Patients were considered as hypertensive if blood pressure was >140/90 mm of hg. Patients were considered as having ischemic heart disease based on ischemic changes in the electrocardiogram (ECG) or by demonstrating hypo kinetic or akinetic segment in the echocardiogram. Ophthalmoscopy was done diagnose diabetic retinopathy. Neuropathy was diagnosed based on subjective symptoms or objective evidence in the form loss of ankle jerks or glove and stocking type of anesthesia. Peripheral vascular disease was diagnosed based on diminished/absent pulses in clinical examination or arterial Doppler. Tuberculosis was diagnosed based on sputum positivity and chest x ray. Fasting, postprandial glucose, fasting lipid profile and other relevant investigations were done in each case.

Patients were followed up regularly in the diabetic clinic. Any change in weight and BMI were recorded. Lean diabetics, whose BMI increased to normal limits after control of hyperglycemia or infection, were considered as normal weight diabetics. Lean diabetics were considered in the group only if their BMI was persistently below 18.5 in spite of control hyperglycemia and after treatment of associated infection causing weight loss such as tuberculosis. Statistical analysis was done using Microsoft excel software. Data is presented in percentage in categories. Statistical tests used included chi square test and ANOVA.

RESULTS:
Out of 500 patients studied, 325 (65%) belonged to normal weight diabetes group, 124 (24%) over weight group, 38 (7.1%) patients were lean diabetics and 13 (2.6%) were obese diabetics.

Mean age of onset of diabetes in lean diabetics was 60.34±13.5 years, whereas it was 58.2±9.8 years for obese diabetics. Lean diabetics were elderly compared to other groups. Values were statistically significant (F value 7.830028, p value < 0.001). There was no significant difference in duration of diabetes in different groups (Table 1) (F=0.8684, p =0.457)

Most of obese diabetics were females (70% of obese diabetics), whereas most of lean diabetics were males (65% of total lean patients). Sex differences in groups were statistically not significant (Table2). Family history of diabetes was present in 62.5% normal weight, 52% over weight, 46% of lean and 45% of obese diabetics.
There was a linear increase in number of patients having abnormal waist hip ratio3 with increase in BMI. Among lean diabetics 48% had abnormal waist hip ratio whereas 79% of normal weight, 80% of overweight and 96% of obese diabetics had abnormal waist hip ratio.

Micro vascular complications were found in similar proportion in all groups (Table3). Retinopathy was present in 27% of lean and 15% of obese diabetics. Neuropathy was the commonest complication among all groups was seen in 35% of lean diabetics, 34% of normal weight diabetics, 32% of over weight and 54% of obese diabetics. Nephropathy was more common in over weight (10.4%) and obese diabetics (15%) Values were statistically significant (p =0.0342).

Table 4 shows macro vascular complications in percentages various groups. Here it was observed that as the body mass increases, the incidence of hypertension and I.H.D. also increases. Incidence of hypertension in lean diabetics was 16.2%, whereas it was 39.09% in normal weight 41.6% in over weight and 61.5% in obese diabetics. Values were statistically very significant (p=0.0002) Incidence of I.H.D was very low in lean diabetics (2.7%); it was 13.84% in normal weight 12% in over weight 23.07% in obese diabetics. However values were statistically not significant (p=0.163) Evidence of peripheral vascular disease was present in 8% of lean and 9% of normal weight diabetics.
Incidence of tuberculosis was very high in lean diabetics (26.6%). (Table 4) whereas tuberculosis was seen in 4% on of normal weight diabetics. Values were statistically very significant (p <0.0001) none of our overweight and obese diabetics had tuberculosis.
It was observed that Fasting and postprandial glucose levels were higher in lean diabetics compared to other groups (Table 5). Values were statistically not significant for fasting but very significant for post prandial glucose (FBS p =0.129 whereas for PPBS p value 0.008)
Lipid profile analysis (Table 6) showed favorable lipid profile in lean diabetics with mean total cholesterol 174.27±68.66 mg/dl, Low density cholesterol (LDL) 97.37±50.66 mg/dl triglycerides 124.28±57.88 mg/dl and High density (HDL) cholesterol 44±15.63 mg/dl. (Table7). As BMI increased from normal to over weight and obese ranges, L.D.L, Triglycerides and total cholesterol showed rising trends. Values were statistically very significant (p <0.0001,0.0001 & 0.00004 respectively)

Table 1: Age of onset and duration of diabetes in different groups.

*Type of Diabetes*	*Age of onset ± S.D in years*	*Duration of Diabetes ± S.D in years*
Lean	60.34±13.52	5.14±5.70
Normal weight	58.30±10.62	6.53±6.91
Over weight	53.22±10.48	7.21±8.10
Obese	58.2±9.80	6.04±6.49
ANOVA test	F statistics 7.83, p =<0.001 ***	F statistics 0.8684,p=0.457 NS

Table 2: Sex ratio in different groups & in % of total cases

*Type of Diabetes*	*Male no /%*	*Females no/%*	*Total number*
*Lean*	26/67%	12/33%	38
*Normal weight*	172/52.8%	153/48.2%	325
*Over weight*	72/58%	52/42%	124
*Obese*	4/30%	9/70%	13
Chi square test	Chi square value 6.87, df=3, p =0.076 (NS)		500

Table 3: micro vascular complications in various groups in total number and as % of cases

*Diabetes type*	*No of cases*	*Retinopathy*		*Neuropathy*		*Nephropathy*
*Diabetes type*	*No of cases*	no	%	no	%	no	%
*Lean*	38	10	27	13	35.13	2	6.6
*Normal weight*	*325*	72.	22	104	31.94	9	2.7
*Over weight*	*124*	25	20	42	33.6	13	10.4
*Obese*	13	2	15.38	7	53.84	2	15.38
Chi square test	Total 500	Chi sq1.097 df= 3, p=0.77(NS)		Chi sq 2.752, df=3, p=0.431(NS)		Chi sq 13.654, df=3,p=0.0342 *

Table 4: macro vascular and infectious complications in various groups in number & percentage

	*Hypertension*		I.H.D		P.V.D		Tuberculosis
*Groups of diabetics*	no	%	no	%	no	%	no	%
*Lean*	6	16.2	1	2.7	3	7.9	10	26.31
*Normal weight*	127	39.09	45	13.84	29	8.9	13	4
*Over weight*	52	41.6	15	12	0	0	0	0
*Obese*	8	61.5	3	23.07	0	0	0	0
Chi square test	chi sq 24.985, df =3, p=0.0002***		chi sq 5.123, df=3, p=0.163 (NS)		chi sq 12.96, df=3, p=0.0047***		chi sq 52.4006, df=3, p<0.0001 ***

Table 5: Showing F.B.S and P.P.B.S in different groups.

*Diabetes*	*F.B.S ± S.D in mg%*	*P.P.B.S ± S.D in mg%*
*Lean*	177.08±105.1	288.45±111.93
*Normal weight*	152.80±54.20	236.58±81.75
*Over weight*	156.18±55.44	226.5±71.23
*Obese*	155.16±35.18	238.17±62.92
*ANOVA test*	F=1.897, p=0.129 NS	F=5.699, p =0.008 ***

Table No 6 lipid profile in different Groups (values in mg%±S.D)

Diabetes	*H.D.L*	*L.D.L*	*Total Cholesterol*	*Triglycerides*
*Lean*	44±15.63	97.37±50.66	174.27±68.66	124.28±57.88
*Normal Wt*	49.18±9.87	134.58±35.11	218.15±42.55	169.96±60.79
*Over Wt*

Chi square test

Diabetes