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and longer exposure to antiretroviral drugs, particularly protease

inhibitors. Only 10% of participants had a BMI > 30 kg/m


, 13 of

141 women and eight of 49 men had abdominal obesity (WC ≥ 80

cm in women and ≥ 94 cm in men).

The study design lacked comparator control groups (e.g. non-

HIV-infected individuals or HIV-infected persons pre-HAART),

making it difficult to determine the independent contribution of

antiretroviral therapy to the MetS and this limits generalisability of

the findings. However, it appears that obesity and the MetS were

substantially lower in HIV-infected individuals, despite the use of

different diagnostic criteria for the MetS.

Studies from other parts of sub-Saharan Africa have generated

wide variations in WC cut-off points. For example, central obesity

defined by WC > 102 cm in men and > 88 cm in women was more

common than generalised obesity (BMI > 30 kg/m


) in Cotonou,



In South Africa, Motala et al.12 found that WC of > 86 cm

in men and > 92 cm in women predicted the presence of at least

two elements of the MetS in a cross-sectional, population-based

study in a rural setting. That study was heavily gender biased, with

80% of the 947 participants being female.

In 2014 Magalhães

et al.



in another cross-sectional study

of 615 university employees in Luanda, Angola, found overall

prevalence of overweight to be 47.8%, and obesity in 45.2%

of participants. Using JIS criteria, crude and age-standardised

prevalence of the MetS were 27.8 and 14.1%, respectively. The

crude and age-standardised prevalence of the MetS was 17.6 and

8.7% using ATP III criteria,


which apply higher WC cut-off points

(≥ 102 cm in men, ≥ 88 cm in women).

Applying ROC curves of WC to detect the MetS, new cut-

off points of this study were 87.5 cm in men (sensitivity 75.9%,

specificity 81.2%) and 80.5 cm in women (sensitivity 88.4%,

specificity 60.5%). The three most common criteria for the MetS

were increased WC, hypertension and low serum HDL cholesterol

levels. Women showed a higher prevalence in all age groups from

the age of 30 years.

The INTERHEART study, a case-controlled study of 27 000

participants from 52 countries, showed a graded and highly

significant association between waist:hip ratios (WHR) and acute

myocardial infarction worldwide.


The association of WHR with

acute myocardial infarction in the INTERHEART study addressed

one of the most fundamental cardiovascular sequelae of excessive

and disproportionate weight. Although the INTERHEART study

investigators cast doubt on the use of BMI in the context of acute

myocardial infarction, obesity, however defined, was associatedwith

a myriad of conditions, including hypertension, diabetes mellitus,

dyslipidaemia, obstructive sleep apnoea, gastro-oesophageal

reflux, sudden death, stroke, certain types of cancer, infertility,

degenerative joint disease and negative psychosocial impact.

The Prospective Studies Collaboration addressed the association

of BMI with cause-specific mortality in about 900 000 adults in

57 prospective studies.


These authors concluded that other

anthropometric measures such as WC and WHR could well add

extra information to BMI, and BMI to them, but that BMI is in itself

a strong predictor of overall mortality rate both above and below

the apparent optimum of about 22.5 to 25 kg/m



For screening purposes, it appears that measurements of WHR

provide no advantage over WC alone, are cumbersome and may be

fraught with errors in field situations. Furthermore, it may not be

necessary to measure WC in persons with BMI > 35 kg/m


since it

adds little value in the predictive power of disease-risk classification.


Inconsistencies in cut-off values for WC have potentially undesirable

consequences for cardiovascular risk stratification, disease

categorisation and prioritisation of preventative strategies for

obesity. There is therefore a strong need for validation of these WC

cut-off values for Botswana before they can be used for prediction

of incident outcomes such as cardiovascular diseases or type 2

diabetes mellitus.

Modelling may help to capture the scope and complexity of

the obesity problem in Botswana. Applications of heterogeneous

adaptive pieces of the puzzle that are affected by and/or influence

the overall behaviour of individuals within society may lead to the

development of empirically based public health models. Agent-

based modelling (ABM) represents one such simplified example.


Using the ABM approach, agents could represent individuals, their

attributes, behaviours and relationships with other individuals in

society. The environment could represent geographical locations,

mobility, domestic settings, market forces and social networking.

Systematic dynamic modelling (SDM) or perhaps more appro-

priately for Botswana, the MicroSimulation model, could be used to

establish temporal and causal associations, if any, between obesity

and related disorders, such as hypertension, diabetes, abnormal


disorders and psychological afflictions.


The strategy focuses on

‘upstream’ preventive approaches rather than ‘downstream’ acute

and chronic care. The goal is to enhance the number of safer,

healthier people and prevent others from becoming vulnerable or

being afflicted by obesity and its related complications.

There are, however, several limitations of this study worth

mentioning. Firstly, this was a retrospective analysis of case notes

of a small number of patients seen at a specialised private medical

practice. The finding may not therefore apply to the general

population. Secondly, WC reflects both subcutaneous and visceral

fat and at best represents a crude surrogate for visceral adiposity.

Because women generally have more subcutaneous fat, there is

a potential risk of misclassifying them as viscerally obese, thereby

resulting in overestimation of the MetS in women. Thirdly, little

is known about the full impact of the obesity epidemic on the

health of the community, and failure to demonstrate statistically

significant links between obesity and existing co-morbidities in this

study should not be construed to suggest benigness of obesity in

this population.


This study reiterates the need for ethnic-specific WC cut-off points

for defining central obesity and, by extension, for diagnosis of the

MetS among black Africans. The proposed WC cut-off values, if

validated, will set the pace for larger studies across sub-Saharan

Africa. Variations in WC cut-off values illustrate the uniqueness of



1. Onen CL. Diabetes and macrovascular complications in adults in Botswana

(DAMCAB). MD thesis 2010, Makerere University, Kampala, Uganda.

2. Garrido RA, Semeraro BM, Temesgen SM, Simi MR. Metabolic syndrome and

obesity among workers at Kanye Seventh Day Adventist Hospital, Botswana.


Afr Med J



: 331–334.

3. Malangu N. Factors associated with metabolic syndrome among HIV-positive

patients at a health facility in Botswana.

Br J Med Med Res



(12): 2352–


4. The World Factbook. Central Intelligence Agency. library/

publications/the-world-factbook/geos/bc.html. (Accessed 19 July 2015).