Association of Neck Circumference with Other Anthropometric Indices and Cardiovascular Risk Factors in Healthy Young Adults

Objectives: To study the importance of neck circumference (NC) for the early detection of cardiovascular disease (CVD) risk factors and to determine the association of NC with other anthropometric parameters and CVD risk factors. Methodology: This cross-sectional study was conducted from July 2018 to June 2019. Total 610 healthy young adults male and females, aged from 18 to 35 years and permanent residents of Shaheed Benazir Abad District of Sindh were randomly selected. Those who had any type of illness, known diabetes and on any medication were excluded from this study. The data including, Socio-demographic, Anthropometric and Biochemical was collected through interview based structured questionnaire which was designed through review of literature of previous studies. Blood pressure was measured by using sphygmomanometer. The blood sample was collected in the morning timings while participants were fasting. The blood sample was analyzed for fasting blood sugar and lipid profile using standard kit methods and according to manufacturer’s instructions. Neck circumference was measured at the upper edge of the thyroid ligament by a non-versatile measuring tape. Consent was obtained before collecting the data, SPSS 18 version was used for the statistical analysis of data. Results: Out of total 610, 313 (51.3%) were male participants and 297 (48.7%) were female Original Research Article Zardari and Laghari; JPRI, 34(22A): 28-36, 2022; Article no.JPRI.83462 29 participants. In male, NC was positively correlated with SBP (r=0.589), DBP (r=0.586), FBS (r=0.358), TG (r=0.606), LDL (r=0.590) and VLDL (r=0.606), however, NC was negatively correlated with HDL-C (r=-0.434). Similarly, in female, the NC was positively correlated with SBP (r=0.552), DBP (r=0.672), FBS (r=0.437), TG (r=0.610), LDL (r=0.592) and VLDL (r=0.610) and LDL(r=0.590) however, NC was also negatively correlated with HDL-C (r=-0.-526) in females. All other CVD risk factors showed significant association with increased NC in both male and female participants. Conclusion: Neck circumference is positively correlated with CVD risk factors in both male and female participants, NC is easy and quick to measure and it can be used as an alternative of other anthropometric parameters.


INTRODUCTION
In spite of the current preventive and treatment measures cardiovascular illnesses (CVD) remains the key cause of morbidity and mortality [1]. It has been estimated that CVD would cause the death of nearly 24 million by year 2023 [2]. It has been reported that among all the illnesses, globally, CVDs are the main leading cause of morbidity and mortality and its prevalence is increasing at alarming rate, around 80 to 86% of these deaths occurs in the low and middle income countries (LMICs) [3][4][5][6].
Large population from developing countries continue to suffer from the burden of cardiac diseases, these countries include Bangladesh, India, Sri Lanka Nepal and Pakistan [5]. Pakistan is a developing nation with huge burden of cardiac diseases, these diseases are mainly due obesity and other modifiable risk factors.
Apparently healthy young adults may have CVD related multiple risk factors. Therefore if these risk factors are screened as early as possible then these young adults can be prevented from CVDs and promoted their health life style [7,8]. In Pakistan thousands of people die each year due to cardiac diseases, it has been reported that the common illness among Pakistani adult population includes hypertension 41%, diabetes 10%, high cholesterol 17.3%, dyslipidemia 34% in male and 49% in females, obesity is 21% so obesity as one of the common illnesses among Pakistani adult population [9,10].
Comparatively novel parameter is neck circumference (NC), which has been reported as the marker for the assessment of metabolic syndrome (MetS) [11,12], and CVD risk factors. Several studies indicate the association of CVD risk factors with age, cigarette smoking, sedentary life style and obesity [9]. BMI and WC are widely used for the assessment of obesity, however, recently Neck Circumference, which is a quick and easy anthropometric parameter have been reported for the assessment of MetS, obesity and CVD risk factors [11,[13][14][15][16][17][18][19]. The purpose of this study is to assess the association of neck circumference with various CVD risk factors. Neck circumference is one the easiest and less time-consuming method to assess the overweight or obese people as compare to usual anthropometric measurement [14]. Shaheed Benazirabad District is located at the northern part of the Sindh province and consists on seven Tehsils.
The novelty of this research is different from other studies is this that, cut off values of neck circumference for this study have been taken from an Indian research paper which describes only association of Basal Metabolic Index (BMI) and Waist Circumference (WC) with neck circumference. However this study has further established the association between already described factors and some other CVD factors which were not given in the Indian research paper as Age, Height, Weight, Waist -to-Hip Ratio, Lipid profile, Fasting Blood Sugar and Blood Pressure [20].

MATERIALS AND METHODS
This observational cross-sectional study was carried out on 610 male and female healthy young adults living in Shaheed Benazir Abad District of Sindh whose age was 18-35 years. They were randomly selected from the different localities of Shaheed Benazirabad District Sindh, which include both urban and rural settings. Out of which 313 were males and 297 were female after approval of ethical committee. The purpose and procedure of the study was explained to the subjects and written consent was taken.

Inclusion Criteria
The healthy young adults of both genders i-e males and females aged 18-35 years.

Exclusion Criteria
The age below 18 and above 35 were excluded from this study. The screening or examination procedures that were carried out before confirming and excluding these cases from the study. Those who were on any medication or drug addicts, pregnant or breast feeding, had a history of neck disease e.g., thyroid disorder, neck surgery or neck malignancy were also excluded from this study.

Anthropometric Measurements
Weight: It was estimated in kilograms (kg) to the closest 0.5 kg on a convenient weighing scale with the subject in light dress and without shoes. Hip Circumference (HC): It was estimated in cm to the closest 0.1 cm, at the degree of more prominent trochanter, with legs near one another by using stretchable measuring tape.

Waist-to-Hip Ratio (WHR):
The waist to hip ratio was determined by dividing waist circumference with hip circumference WHR= waist circumference/ hip circumference.

Biochemical Measurements
At morning venous blood sample after an overnight fast (10-12 hours) was drawn and centrifuged for 15 minutes at 2200-2500 rpm. Fasting blood sugar was estimated by using glucose oxidase-peroxidase method [22]. Lipid parameters such as total cholesterol (TG), Triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LD-C), and very low-density lipoprotein cholesterol (VLD-C) and fasting blood glucose (FBG) were estimated by a standard enzymatic method on an autoanalyzer (Microlab 300).

RESULTS
An observation based cross sectional study was conducted on 610 healthy young adult males and females of Shaheed Benazirabad district of Sindh, Pakistan. Among 610 healthy young adults' males were 313(51.3%) and females were 297(48.7%). The healthy subjects were divided into three age groups 18-23, 24-29, and 30-35 years, the number of males was greater in age group 30-35 years 134(42.8%) whereas the number females was higher in age group 18-23 years 222(74.7%) as shown in  Table 2. Shows Pearson's correlation between NC and others continuous variables including body Weight, Height, BMI, WC, HC and Waisthip Ratio (WHR). In male subjects, neck circumference was weakly positively correlated with height (r=0.188), strongly correlated with weight (r=0.785) strongly correlated with BMI (r=0.816), strongly correlated with WC (r=0.801), strongly correlated with HC (r=0.773) and strongly correlated WHR (r=609). Where as in female subjects neck circumference was positively moderate correlated with WHR (r=0.463) and positive strongly correlated with weight (r=0.701), BMI (r=0.763), WC (r=0.784), HC (r=0.686). All values are significant, however height was not significantly correlated with NC in females (P>0.05).

DISCUSSION
Evidence has shown that raised serum triglycerides, BMI, WC and reduced level of HDL are strongly reflect the elevated neck circumference (NC) [23]. The present study indicates the connection between the variations in NC and variations of few variables of the CVD factors. The cut off of 36.50 cm in males and 32.50 cm in females from the population of Asian Indian origin were used in this study [20]. Many studies on anthropometric measurement have been undertaken, but none have compared NC to other anthropometric measurements or its relationship with CVD risk factors in Pakistan. Hingorjo-et al has conducted study in youngsters (18-20 years) to find out the Neck Circumference as marker of obesity but he did not compared with lipid profile, Fasting blood sugar and Blood pressure [24]. In this study NC was strongly correlated to other anthropometric parameter such as BMI, WC, HC and Waist-to-hip ratio and risk factors for CVD such as BFS, SBP, DBP, and lipid profiles elevated level from normal shows more than 50% NC was abnormal > 36.5 cm in male and >32.5 cm in female according to Indian Asian cut off values. Abnormal NC was found more in percentage in male than female.
Many people die every year in Pakistan due to many cardiac diseases. This study shows strongly correlation between NC and CVD risk factors in healthy young adults. So, NC is simple safe, non-invasive technique for early detection of CVD risk factors. Therefore, very good number of morbidity and mortality due to CVD can be prevented.

CONCLUSION
NC was strongly associated with other anthropometric indices and in elevated CVD risk factors. So, neck circumference is an independent index for early finding of CVD risk factors in healthy young adults.

CONSENT
As per international standard or university standard, Participants' written consent has been collected and preserved by the author(s).

ETHICAL APPROVAL
As per international standard or university standard written ethical approval has been collected and preserved by the author(s).