Recruitment of subjects: The study was conducted on the patients attending the OPD of Apollo Institute of Medical Sciences and Research, Chittoor, Andhra Pradesh. Ethical clearance was obtained from the Institutional Ethical Committee (Number: IEC12/AIMSR/05/2019). Informed consent was taken from each of the participants. A total of 124 participants were recruited for the study.

The history of hypertension, diabetes, coronary artery disease, smoking and alcohol intake was taken. Anthropometric measurements included height and weight measurements and BMI was determined according to kilogram per meter square. Waist and hip circumference were measured using standard techniques and the WHR was calculated [8]. The blood pressure was recorded using a mercury sphygmomanometer in sitting posture [9]. They were categorised into cases and controls on the basis of Ankle Brachial Pressure Index (ABPI) [10]. Doppler studies were performed on both upper and lower limbs and the ABI was calculated.

Inclusion criteria: All adults residing in Chittoor town with age 18 years and above attending the OPD and the subjects having ABI value of <0.9 were considered as cases of PVD. An ABI value of 0.9 to 1.14 was taken as the cut-off value for controls and were included in the study.

Exclusion criteria: Bilateral upper/lower limb amputees/absence of limbs, critically-ill patients, pregnant and lactating women and the patients with history of cerebrovascular accidents were excluded from the study.

Data was entered in MS excel and analysed using SPSS version 22.0 software. Chi-square test was used as the test of significance. A p-value <0.05 was considered as statistically significant.

A total of 124 participants were included in the study, among which 62 participants were cases having PVD identified by ABI less than 0.9, and 62 participants were controls having ABI ≥0.9. Comparison of demographic factors between cases and controls are presented in [Table/Fig-1]. The mean age of the subjects among cases was 59.94 years and among controls, it was 61.29 years. Individuals of both the groups were of the same demographic frequency.

The mean systolic blood pressure was higher in cases (140.4±8.04 mm of Hg) compared to controls (137.7±8.12 mm of Hg), but the difference was not significant statistically. However the mean diastolic blood pressure was significantly higher in cases (85.0±7.44 mm of Hg) than controls (81.5±6.73 mm of Hg). A significantly higher number of cases (54.8%) were smokers as compared to controls (17.7%). Similarly, a higher number of cases (33.9%) were consuming alcohol compared to controls (16.1%). A significantly higher number of cases were having diabetes mellitus and hypertension compared to controls [Table/Fig-2].

In both cases and controls, a greater number of participants were in obesity grade I (45.2% cases and 58.1% controls). The number of participants with grade II obesity is more in cases (38.7%) compared to controls (8.1%). A significantly higher number of cases were in higher BMI categories (obesity grade I and grade II) compared to controls. Mean waist circumference, hip circumference was significantly higher in controls compared to cases. But, WHR did not show any significant difference between cases and controls as the majority of the subjects were within the normal cut-off values of WHR in both cases and controls [Table/Fig-3].

It was derived from observations of this study that PVDs are correlated positively with BMI. Further, there is evidence that it is the peripheral fat mass that is positively correlated with PVD and not the central obesity or abdominal obesity. Patients with PVD had lower waist circumference values as compared to controls but higher BMI. This finding possibly indicates a reduction in abdominal fat in PVD cases due to various reasons or accumulation of fat in the lower extremities. The causes of greater distribution of fat in lower extremities may be due to the functional impairment (disuse) caused by the disease [9]. Similar findings were observed in some studies. In a study done by Jayanthy AK, et al., it was found that BMI is directly related to ABI in PVD patients which is in agreement with the present study [10]. Lu B et al., showed that WHR increases the risk of PVD in men and higher WC increases the risk of PVD in women [11]. However, some studies have reported BMI as a protective factor for PVD [12] while many others reported that the association between obesity and PVD was not significant [13].

In cases of PVD, over a period of time leg muscle is replaced by adipose tissue due to physical inactivity, genetic factors, associated neuropathy and other co-morbid conditions. These observations are in agreement with earlier studies which show that PVD patients with significant ABI discrepancies have lower calf muscle area and higher calf muscle percent fat in the leg with severe ischaemia [9]. In the same study it was found that PVD participants had lower calf muscle density, lower calf muscle area, and higher calf fat and were associated with decreased mobility at two year follow-up. In a study done by Golledge J et al., it has been reported that obese patients with PVD were associated with reduced mortality as compared to underweight patients with PVD [14]. In a study done by Anusruti A et al., it was found that reactive oxygen metabolites (determinant of high oxidative stress in obese individuals) were independent of the participant’s weight [15].

Despite this, several studies have shown the obesity survival paradox, showing the association between higher BMI and survival. The role of obesity in PVD outcomes is also not well-established, but some studies have shown clear survival benefits [10]. Some of the possible explanations are that obese patients are more likely to seek medical care at an earlier stage because of other co-morbid conditions which potentially influence long-term outcomes. More aggressive treatment and medication in this population may lead to a reduction in unfavourable outcomes. High level of suspicion and better screening have reduced the time of diagnosis drastically and hence they tend to take better precautionary measures. The other well known risk factors like diabetes, hypertension and smoking were associated directly with PVD.

In a study done by Criqui MH et al., it was shown that diabetes was significantly associated with PVD [16]. American Diabetes Association reported diabetes mellitus as the strongest risk factor of PVD [17]. Dyslipidaemia also has been identified as a significant risk factor for PVD in many studies. Ridker PM et al., reported dyslipidaemia as an independent risk factor [18]. Some studies have reported hypertension as a significant risk factor of PVD [19-21]. Smoking is a well known risk factor for PVD. It showed significant relation with PVD in the present study. Among cases in the age group of 61-70 years, there was a significant correlation with history and duration of smoking. A similar finding was observed with the controls. In both these instances, they had a lower ABI. This clearly indicates smoking as a very important risk factor which plays a key role in the pathogenesis of PVD. Many studies have identified smoking as a potent risk factor of PVD with consistent dose response relationship. In a study done by He Y et al., it was reported that both current smoking and former smoking was a significant risk factor of PVD [21]. A systematic review done by Willigendael EM et al., found that the prevalence of PVD had increased by two-three folds among current smokers compared to non-smokers and a clear dose-response relationship was seen [22]. Similar findings have been reported in previous studies also [23]. A higher number of cases were consuming alcohol in the present study, however Fabsitz RR et al., showed that current alcohol consumption is negatively associated with PVD [24].

Firstly, the other measures of obesity like waist-to-height ratio and waist-to-thigh ratio were not measured. Secondly, a larger study population would have given more consistent results. Thirdly, the data regarding the physical activity levels of the subjects were not obtained.

The findings obtained from this study suggest that PVD is not associated with central obesity instead it is associated with peripheral fat mass. Further, BMI, diabetes, hypertension and smoking were significant risk factors for PVD. Though the WC was lower among the cases of PVD, the accumulation of fat in the lower extremities could have possibly contributed to higher BMI in these individuals. Further studies in relation to the pathophysiology of PVD and the correlation of these results with other obesity indices are needed to come to a proper conclusion.