Relationship between the Neck Circumference, StandardAnthropometric Measures, and Blood Pressure in youngadults in Urban slums, Bengaluru

Introduction

Obesity is associated with cardio metabolic risk and is strongly associated with diabetes, dyslipidemia, and hypertension. Basal metabolic rate is used to assess for overweight and obesity, but it does not differentiate between fat and other tissues. Waist circumference may be better for predicting obesity-related health risks than BMI. But measurement of waist circumference (WC) has substantial variability. Neck circumference measurement is easy to perform, quick, reliable, and inexpensive. Higher metabolic risk is seen in individual with upper body subcutaneous fat (UBSF) which is estimated by NC than abdominal visceral fat. According to observation done by some studies NC plays an independent correlation of risk factors than body mass index (BMI) and waist circumference.^1-5

In busy everyday primary care practice, NC can be used as a convenient tool to define and grade overweight and obesity. So this study is done to assess an impact of gender on NC values and to determine whether the NC correlates with standard anthropometric measures and BP values in apparently healthy young adults.

Materials and methods

A cross-sectional study included young adults of 19 to 24 years in Urban slums of Bengaluru conducted during the month of October – November 2019 by snowball sampling.⁶ A face validated semi structured self-administered questionnaire consisting information regarding general characteristics, lifestyle characteristics (smoking, alcohol consumption, and physical activity), anthropometric characteristics, BP values, and a family history of cardiovascular diseases and diabetes mellitus were recorded in the questionnaire. To measure the NC participants were made to stand erect, in light clothes, and without shoes. Standard plastic tape was used to measure the NC. During measurement, the head was positioned in the Frankfort horizontal plane. The top edge of a plastic tape was placed perpendicular to the longitudinal axis of the neck and just below the laryngeal prominence.⁷ Digital scale was used to measure weight in barefoot. Plastic tape was used to measure waist circumference. Body mass index (BMI) was calculated as weight (kilograms) divided by the square of height (meters). The BP was measured by trained personnel in the morning hours (8:30 to 11:30). A standard mercury-column sphygmomanometer was used for the BP measurement. During BP measurement, participants were in the sitting position. The BP was measured three times, and the average of the three BP measurements was calculated. Essential hypertension was defined as an average SBP≥140 and/or average. Ethical approval was obtained from the Ethical Committee of Bengaluru Medical College & Research Institute.

Inclusion criteria: participants for the study were healthy individuals between 19 and 24 years of age of both genders dwelling in urban slum.

Exclusion Criteria: Individuals having neck deformities and goiter and also subjects with a history of thyroid disease and other co-morbidities like diabetes, dyslipidemia, hypertension, or other diseases were excluded from the study.

Data analysis

Data was tabulated in MS Excel & coded. Analysis was done using statistical software SPSS version 20.0. Results were expressed in terms of percentages, tables and graphs using appropriate statistical tests.

Results

The sample comprised a total of 102 participants (46 males and 58 females). Gender differences in the BMI, WC and DBP values were significant. Significance was not found in difference between the genders for SBP values. (Table 1)  

In 46 young men, the value of NC was 36.68±1.47 cm, while in 58 young women, the value of NC was 32.12±1.63 cm with p<0.001 which demonstrates the significance in difference in NC value among male and female gender.(Figure 1)

A significant positive correlation was found in healthy young participants between the NC and BMI and WC but positive correlation was not found between the NC and the SBP and DBP.(Table 2).

Discussion

The NC value determined in healthy young adults of male gender was 36.68±1.47 cm, while the determined NC value in healthy young adults of female gender was 32.16±1.83 cm (p<0.001). There are no adequate studies to prove the relation of NC but our results are in a compliance with a study conducted among Bosnian Young Adults of 19 to 24 years in which significant gender differences with regard to NC values were observed. For obesity estimation NC is a new anthropometric index.⁸ Subjects will experience discomfort while measuring standard anthropometric parameters which is not so while measuring NC.⁹ A positive correlation have been observed in adult individuals of general population between NC values and values of standard anthropometric obesity parameters.^9,10 Our study shows a positive correlation between the NC and BMI and WC values in healthy young adults of both gender which are compliance with results obtained from the study by Hingorjo et al.¹¹ A positive correlation which is observed between NC and WC values in our study propose possible use of NC as an indicator of central obesity in healthy young adults. Still some confounding factors such as difference in dietary practices, cigarette smoking, alcohol intake, and physical activity were collected in the questionnaire but were not included in assessment of the present study, and this may be a potential source of bias. A similar future study should take into consideration all these factors.

Our study results did not determine a significant correlation between the NC and SBP and DBP values in healthy young adults. But some recent studies like Fan et al.¹² showed significant correlation between NC and BP after adjustment for BMI, WC and waist-to-hip ratio in Chinese adults.

The limitation of our study is a small sample size consisting of healthy young adults from a select population. Therefore, obtained findings cannot be generalized for an entire population.

Conclusion and recommendations

NC can be considered as a simple, useful, and reliable tool to identify overweight and obesity instead of standard anthropometric measures like BMI and WC which causes discomfort during measurement. Large prospective populationbased studies are still required to corroborate our findings

Source of funding: None.

Conflict of interest: None.