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Introduction
Methods
Results
Discussion
Conclusions
Recommendations
References
Discussion
Antonio Berdasco
Department of Human Growth and Development, J. Trigo School of Medicine, Institute of Medical Sciences, Havana, Cuba
An anthropometric study was carried
out on 31 662 male and female adults from 20 to 60 years of age, living in Cuba's 14
provinces. Measurements were taken utilizing the methods and equipment recommended by the
UN International Biological Programme. Weight/height, body mass index (BMI), Rohrer,
Sheldon, Ponderal and Benn indices were registered as well as their correlation with
height, weight and fat folds in order to obtain the suitable index for nutritional
evaluation. The BMI was selected as the most appropriate and its values were recorded by
sex, age, dwelling, educational level and type of occupation. The cut-off points of
'normal' BMI values were determined. Their range, based exclusively on anthropometric
data, in general coincided with those defined by international actuarial data. The
distribution of BMI values was very similar to that of developed countries with more
overweight than underweight individuals, particularly in females. Rural populations were
lighter than those in urban communities and had more underweight subjects. Lower
educational levels were directly related to higher percentages of chronic energy
deficiency (CED) in women; in men, there was no defined trend. On the contrary, in men CED
was slightly more related to jobs that required light effort; in women there was no
defined trend. Finally, a model of action against malnutrition is proposed.
There are several nutritional problems in adults. In
developed countries (Miller & Stephens, 1987) obesity is the most frequent and
constitutes a health problem that has been discussed and analysed in terms of definition,
possible causes, diagnosis, impact on health and longevity. Such issues must be
investigated to better understand the causes of obesity, and how to facilitate its
prevention (National Institute of Health, 1985).
The other side of the problem is the high incidence of undernutrition in developing countries. Undernutrition, especially if it is severe, is linked with many physiological, behavioural, sociological and economic problems. Consequently, it is very important to select the best tool to estimate its real incidence in an easy and effective way. This is a first step before taking action to solve such an enormous social and health problem facing the world's population, especially in developing countries.
To know the desirable or 'normal' physical characteristics of adults is very useful in determining the nutritional condition and health status of a group of people. Weight has been the most widely used and when relating to height and sex it has increased value as a tool in nutritional studies. The best weight/height index is the one having the lowest correlation with height and the highest with weight (Lee, Kolonel & Hinds, 1981; Miccozzi et al., 1986). Although not uniform, higher correlations are found between BMI and weight/height index with weight or fat folds than with height. (Keys et al., 1972; Frisancho & Flegel, 1982; Miccozzi et al., 1986.)
In our country, national studies on growth and development (Jordan, 1979; Berdasco et al., 1991) have yielded adequate data on both children and adults to allow appropriate analyses. The study of the children's parents in the sample of the second national growth and development Cuban study of 1982, yielded data on Cuban adults of both sexes from 20 to 60 years of age. This allowed us to examine other anthropometric variables as well as the weight/height indices of these individuals.
We decided to analyse characteristics that change with age, the style of life and the environmental conditions. It is important to determine which environmental differences affect adult anthropometry. In Cuba, as in the case of children and adults of many countries (Eveleth & Tanner, 1976; Bielicki, 1986), individuals from rural areas are usually found to be less physically developed. Differences between adults performing physical work of varying intensity are also expected. Lastly, differences in the relationship of physical characteristics to educational level are important. This might not only reflect the degree of training for jobs differing in their physical requirements but also the graded effects of different cultural levels with different nutritional knowledge, aesthetic concepts etc. Understanding these relationships may affect public policies aimed at achieving or maintaining optimum patterns of physical development.
Another reason why the study of
adults in Cuba, and especially adults aged 20-60 years of age is necessary, is that this
age group comprises the country's basic productive and service sector of the population,
that is, 46.9% of the total as shown in the 1981 National Census (Comité Estatal de
Estadisticas, 1984). In this paper, we shall limit our analysis to the variations in BMI,
and particularly low BMIs in relation to the sex, age, height, dwelling, educational level
and physical working activity linked to occupation. We shall also estimate the cut-off
points of 'normality' for our population.
Subjects
The parents of the subjects selected for the sample of the second growth and development study (Berdasco et al., 1991) were the subjects of this survey. After cleaning the data, the total number of adults was 31 662, of whom 11912 were males and 19 750 were females. This difference in the numbers was probably due to the better attendance of mothers for their appointments.
Field work
The adults attended the measuring centres where they were weighed, and had their height, upper arm circumference, triceps and subscapular fat-folds measured. The survey was undertaken by eight measuring teams (two anthropometrists each) working simultaneously from May to December 1982. Individuals living in the country's 14 provinces were measured.
In order to assure the best possible quality in the primary data, anthropometrists were trained in the same measuring procedures utilized in the first national growth and development study (Jordan, 1979), namely, those recommended by UN International Biological Programme (Weiner & Laurie, 1969). The quality of the measurements was also guaranteed through technical supervision by the investigators, and two quality control sessions. In this way, a correct application of measuring techniques was assured and consequently, consistent and uniform measurements were obtained. The adults were measured without shoes and with the lightest clothing possible (underwear and trousers or skirt) from which their nude weight could be estimated as 1 kg less than the recorded weight.
Criteria to define urban or rural dwelling
The basic definitions of the 1981 Cuban Population and Housing Census were used (Comité Estatal de Estadisticas, 1984).
Urban dwellings were categorized as:
(a) all places with a population of 2000 or more inhabitants;
(b) all places with a population of 500 to 2000 inhabitants with electricity and three or more facilities such as an aqueduct, paved streets, a sewerage system, medical services and an educational centre; or
(c) all places with a population of 200 to 500 inhabitants with electricity and all of the five facilities listed in (b).
All places with a population of less than 200 inhabitants were considered rural. This category also included places with a population between 200 and 2000 inhabitants and without the facilities available in urban places.
Classification criteria related to educational level
Adults were classified into the following four groups based on the last grade passed:
Group 1: 12th or over (high school graduates, university graduates or students)
Group 2: 9th to 11th (junior high school graduates)
Group 3: 6th to 8th (junior high school not completed; elementary school graduates)
Group 4: 6th grades (elementary school not completed).
Classification criteria related to the type of occupation
Occupation was recorded by questioning the subjects at an interview. They were then classified as follows:
Group 1: Production and service workers (moderate to intense physical activity)
Group 2: Professional, technical and administrative workers (light physical activity)
Group 3: Agricultural workers and small farm workers (mainly intense physical activity)
Group 4: Housewives and students.
Data processing
After cleaning the data, the following indices were calculated: weight/height, Rohrer, Sheldon, Ponderal, Benn (data not shown except for BMI). Correlations were established (Pearson's linear correlation coefficients) with weight, height, triceps fat-fold, subscapular fat-fold and the sum of both fat-folds.
Percentiles 3, 10, 25, 50, 75, 90, 97 of BMI were estimated for each year of age, by sex and by sex and place of dwelling i.e. urban and rural. Calculations were also made by 10 year groups categorized by sex and by sex and place of dwelling. Classification of the BMI was also carried out with the cut-off points proposed by James, Ferro-Luzzi & Waterlow (1988) for CED:
CED 3 BMI <16.0
CED 2 BMI 16.0-16.9
CED 1 BMI 17.0-18.4.
To this classification were added the following categories:
Underweight BMI 18.5-19.9
Normal BMI 20.0-24.9
Obese 1 BMI 25.0-29.9
Obese 2 BMI 30.0-39.9
Obese 3 BMI 240.0.
These groupings were used to
classify BMI by 10 year intervals and by sex, sex and place of dwelling, sex and
educational level, sex and occupation, sex and height (where the shortest < percentile
3, and the tallest were > percentile 97). Another classification was also made by
percentiles of BMI and height by sex. Finally, the cut-off points of 'normal' BMI for the
Cuban population were estimated by the percentage distribution of individuals by category
of fat-folds in relation to the BMI groups and by sex and two age groups, 20-39 and 40-59
years. More detailed information of the data processing may be found elsewhere (Berdasco
& Romero, 1992).