The SA Journal Diabetes & Vascular Disease Volume 17 No 1 (July 2020)

RESEARCH ARTICLE

SA JOURNAL OF DIABETES & VASCULAR DISEASE

VOLUME 17 NUMBER 1 • JULY 2020

and alteration in lipid profile may be implicated in visceral fat

distribution and increased BP values.

20-22

Most studies suggest that

centrally located body fat is a stronger determinant of BP elevation

than peripheral body fat in both men and women.

21,23

A positive correlation between BMI and BP has been reported

among Ghanaian adults aged 30 to 50 years old.

Certain

occupations, especially white-collar jobs, are characterised by sitting

for long periods of time, such as employees in financial institutions

and administration offices, and this predisposes individuals to a

sedentary lifestyle.

These individuals tend to spend the majority of

their adult working lives less engaged in physical activity outside of

working hours, thereby predisposing them to obesity and diseases.

A study in India reported a higher prevalence of hypertension,

which was more positively correlated to obesity among employees

than the general population of the country.

A recent systematic review among workers in West Africa

reported a prevalence of hypertension of 12 to 69% among

employees.

The prevalence of obesity ranged from 2% among

automobile garage employees in Kumasi, Ghana,

to 42.1%

among healthcare workers in Umuahia, Nigeria.

The prevalence

of hypertension ranged from 27.9 to 78.9% among obese workers

compared with 7.3 to 65.4% among non-obese employees in

West Africa.

Among healthcare workers in a university teaching

hospital, there appeared an unusual ratio in the association between

obesity and hypertension, which was 2.2 (

= 0.004).

In Kaduna,

civil servants younger than 40 years old who were overweight or

obese were five times as likely to have hypertension compared with

healthy-weight workers.

Schutte

et al

reported a prevalence

of 48% overweight and obesity among South African employees

from 18 companies participating in healthscreening programmes.

Cardiovascular risk factors, specifically diabetes and hypertension,

were found to be associated with obesity among public service

workers in Ondo State, Nigeria.

This study will be first of its kind to study employees in the

Vhembe district municipalities of the Limpopo Province to

investigate the relationship between obesity and BP.

Methods

The research was based on a cross-sectional design on an available

population sample of local government employees in the Vhembe

district municipality of the Limpopo Province, South Africa.

Participants voluntarily participated in the study.

There were 452 (men = 207; women = 245) participants from

local government employees in the Vhembe district, which is one

of the five districts of the Limpopo Province of South Africa (local

government is a form of public administration in South Africa,

which exists as the lowest tier of administration in the provinces).

Vhembe district is located in the northern part of the country and

shares its borders with the Beitbridge district in Matabeleland

south, Zimbabwe. According to the 2001 census, 800 000 Vhembe

district residents speak Tshivenda as their mother tongue, while

400 000 speak Tsonga and 27 000 speak Northern Sotho.

The

majority of the participants in this study were employed as grounds

maintenance workers, clerical workers, managers and councillors.

The employees were categorised into three age groups as follows:

24–29, 30–44 and 45–65 years. Participants were included in the

study if they were within the age categories and deemed healthy.

Standing height was measured to the nearest 0.1 cm, using a

Harpenden portable stadiometer (Holtain Ltd, Crymych, Dyfed, UK).

Body mass was measured using a portable calibrated scale (SECA)

and recorded to the nearest 0.5 kg. BMI was calculated as body mass

(kg) divided by height (m) squared (kg/m²).

Waist circumference (WC) was measured using a steel tape

measure and in accordance with the procedure recommended by

the American College of Sports Medicine.

For men, low WC in

this classification is defined as less than 94 cm, high is 94 to 102

cm, and very high is greater than 102 cm. For women, low WC is

less than 80 cm, high is 80 to 88 cm, and very high is greater than

88 cm.

38,39

Waist-to-height ratio (WHtR) was determined from waist

circumferences (cm) divided by height (cm). The norms for WHtR

were as follows: normal is WHtR < 0.5, while WHtR > 0.5 indicates

increased risk for both males and females.

BP was measured by using an automated sphygmomanometer

(Omron, Health Care, Inc, USA). The participants were seated, and

systolic (SBP) and diastolic (DBP) blood pressure measurements

were determined according to the protocols suggested by the

American College of Sports Medicine (ACSM).

The ACSM has identified thresholds above which individuals may

be at an increased risk for cardiovascular disease.

The thresholds

that were used to describe risk included the following:

• overweight = BMI between 25 and 29.9 kg/m

; obesity = BMI ≥

30 kg/m²

• hypertension = SBP ≥ 140 mmHg and DBP ≥ 90 mmHg, as well

as for participants on hypertension treatment.

The aim of the study was explained to the participants and their

employers, who were also informed that the data would be treated

confidentially and would only be used for the purposes of research.

The participants were requested to complete and sign an informed

consent form before participating in the study. The measurements

took place during weekdays, as arranged with the participants. The

researcher (a biokineticist registered with the Health Professions

Council of South Africa: registration number BK 0016195-HPCSA)

was assisted by well-trained research assistants conducting the

measurements. The anthropometric measurements of height,

weight, WC and BP were taken in allocated separate rooms for

males and females. The study received ethical approval (Ref: NWU-

00125-13-S1) from the ethics committee of North West University,

Potchefstroom, South Africa.

Statistical analysis

Descriptive statistics were calculated for all variables according

to gender. Numerical data are expressed as mean and standard

deviation (mean ± SD) and categorical data are expressed as

percentages. A

-test was used to determined differences in the

means of variables (age, height, weight, BMI, WC, WHtR, and SBP

and DBP between the study groups), and the chi-squared test was

used to compare the prevalence of general obesity and central/

abdominal obesity in men and women. The differences in BMI

and WC across age groups were described by gender, and the

chi-squared test was used to compare the prevalence of obesity

between the various age groups. To determine the differences

between the BMI categories/groups, an analysis of variance

(ANOVA) was calculated for all variables. Descriptive characteristics

of the hypertensive and normotensive groups were determined and

compared. Pearson correlation coefficients were used to determine

the relationship between obesity and BP among employees. All

statistical analyses were performed with the SPSS, version 21. The

statistical level of the p-values was set at

≤ 0.05.