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SA JOURNAL OF DIABETES & VASCULAR DISEASE
RESEARCH ARTICLE
VOLUME 16 NUMBER 1 • JULY 2019
19
2015, senior Northern Sotho-speaking dietetics students of the
University of Limpopo, specifically trained in using the 24-hour
recall method, interviewed the parent/caregiver at home regarding
the dietary intake of the young adults over the previous 24 hours.
For each participant, an interview took place on one weekday and
one weekend day. An average of two days of 24-hour dietary intake
was then taken for each participant.
Estimated portion sizes of foods consumed were recorded in
as much detail as possible, using a pre-tested questionnaire and
food models simulating average portions of local foods.
15,16
Dietary
data were analysed using local food tables and Food Finder dietary
software, and compared with recommended intakes.
15-18
Statistical analysis
Variables were summarised as descriptive statistics. Linear regression
models were used to assess the continuous association between
dietary intake and BMI, while logistic regression models were used
to assess the association between low/high dietary intake and
prevalent overweight and obesity, both in invariable analyses and
after adjusting for age and gender. All data were analysed using the
statistical package for social sciences (SPSS) version 23 and a
p
-value
< 0.05 was used to characterise statistically significant results.
Results
The mean BMI was 20.3–21.9 kg/m
2
in males and 23.2–28.1 kg/m
2
in females (
p
≤ 0.05). Mean BMI increased from 20.3 kg/m
2
in the
age group 18–20 years to 21.9 kg/m
2
in the age group 27–30 years
in males, and from 23.2 to 28.1 kg/m
2
in females (Fig. 1).
The distribution of BMI categories in the overall sample was
8.6–20.5% for underweight, 9.3–23.1% for overweight and
3.1–25.8% for obesity. Equivalent figures were 20.5, 61.7, 9.3 and
3.1% in males, against 8.6, 43.5, 23.1 and 25.8% in females (
p
≤
0.05 for the difference in the distribution of BMI categories in males
and females) (Fig. 2). Males had a higher incidence of underweight
(20.5%) than females. However, females (23.1 and 25.8%) showed
a higher incidence than males (9.3 and 3.1%) of overweight and
obesity, respectively.
Fried chicken (23.8%), pap (22.6%), cold drink (16.9%) and
white sugar (14%) were the foods most frequently consumed by
the young Ellisras adults, while samp (2.6%), yogurt (2.4%) and
spinach (2.0%) were the least frequently consumed foods (Table 1).
Carbohydrates ranged between 78.2 and 84.5% while total fats
and saturated fats ranged between 31.6 and 42%, and 4.1 and
6.0%, respectively, for all BMI categories for the overall population
(Fig. 3).
In linear regression analyses, there was a borderline positive
association between cholesterol intake and BMI (
p
= 0.058), with
further enhancement after adjustment for age and gender (beta =
0.002,
p
= 0.035) (Table 2). Table 3 presents logistic regression for
the association between overweight/obesity and low dietary intake.
In logistic regression analyses, there was a positive association
between cholesterol intake and overweight and obesity (
p
=
0.084), and after adjustment for age and gender, the association
of cholesterol intake with overweight and obesity was significant
(
p
= 0.020) (Table 3).
Discussion
This study aimed to investigate the relationship between dietary
intake and BMI among young rural Ellisras adults aged 18 to 30
years. There was a significant association between cholesterol
intake and BMI. Furthermore, a high prevalence was reported of
overweight and obesity among females compared to males in the
Ellisras population. These findings were in line with previous studies
conducted in rural black communities in the Limpopo province.
3
This may be due to culture-related attitudes, physical inactivity,
poor nutritional value of food, and high intake of calorie-dense
food in rural populations.
3
Fig. 1.
Descriptive statistics of mean body mass index by age group and gender
among young rural Ellisras adults aged 18–30 years.
Fig. 2.
The prevalence of malnutrition by gender among young rural Ellisras
adults aged 18–30 years.
Table 1.
The most frequent food items in the diets for the overall
sample, from the most common food liked to the least liked
Variables
Percentage
Fried chicken with skin
23.8
Pap
22.6
Cold drink
16.9
White sugar
14
Vetkoek
5.8
Fried beef
4.7
Peanut butter
4.4
Samp
2.6
Yoghurt
2.4
Spinach
2.0
Pilchards
0.5