Factors related to weight status of Bahraini adults were studied.  A cross-sectional survey on 514 Bahraini adults aged 30.79 years was carried out using multistage sampling technique.  Body mass index was used as an indicator for measuring obesity.  The subjects were classified into non-obese (BMI<25), overweight (BMI 25-29.9) and obese (BMI>30).  There was a significant difference in mean BMI between men and women in all factors studied.  Younger people (30-49 years), with higher education, non-smokers, those with history of hypertension, and those who watched television daily had higher mean BMI.  There was a significant difference between weight status and age (p<0.005), sex (p<0.0001), education (p<0.04), smoking (p<0.0001), hypertension (p<0.001), diabetes (p<0.001), and watching television (p<0.03).  The results suggest that the health authority in the country should establish a programme to prevent and control obesity, taking into consideration several social, dietary and health factors.

Bahrain Med Bull 2000;22(3):

Several studies have been carried out in Bahrain to determine the prevalence of obesity in the population1-3.  These studies found that obesity is highly prevalent among adolescents and adults, especially among women.  As obesity is a risk factor for some chronic diseases4, the need to prevent and control it has become an essential measure to prevent chronic non-communicable diseases in the country.

Any programme to prevent obesity would not be effective without understanding the factors that cause overweight and obesity among various age groups.  Very few studies have addressed this aspect in Bahrain.  Musaiger et al5 studied socio-demographic and dietary factors associated with obesity among secondary school students (15-20 years) in Bahrain.  The findings revealed that 15.6% of boys and 17.4% of girls were either overweight or obese.  Family size, parents' education, and family history of obesity were significantly associated with obesity among boys, while family history was the only socio-economic factor statistically associated with obesity among girls.  Another study on women attending physical fitness programmes in Bahrain showed that age, education, employment, marital status, family size and practising exercise have a statistically significant association with obesity, whereas ownership of cars, availability of housemaids, family history of obesity and meal patterns have no significant association6.

The objective of this study was to investigate some factors that might be associated with the weight status of Bahraini adults aged 30-79 years, using a community-based survey.

METHODS

The study population consisted of Bahraini nationals aged 30-79 years.  A proportional random sample of 520 households taken from a list of all households in Bahrain released by the Central Statistics Organization7 was selected using the method for cluster sample surveys described by Bennett et al8.  In brief, Bahrain is divided administratively into 11 geographical areas, a total of 337 blocks. A random sample of 52 blocks (15%) was selected using random tables. A probability random sample was obtained from lists of households in each of the selected blocks, and 10 households were chosen from each block, yielding a total sample of 520 households.

One person aged 30 to 79 years was selected from each household.   This was done by selecting the first person available in the household  aged 30 years or above.  People were interviewed at home by trained female interviewers using a structured pre-tested questionnaire which included information on socio-demographic backgrounds, lifestyle patterns, and history of diabetes and hypertension. Educational levels of subjects were grouped into three categories, low education, which included illiterate and those who could read or write; middle education which included those who had primary and intermediate education, and high education, which included those who had secondary and university education. Marital status was divided into two groups; currently married and unmarried (including widowed and divorced). Smoking behaviour was classified into two categories, current smokers and current non-smokers (including ex-smokers). Six people were excluded due to incompleteness of some responses to questions, making the total sample of 514 people.

Weight was obtained using a scale with an accuracy of 0.1 Kg, while the height was obtained using a portable stadiometer with an accuracy of 0.1 cm. Body mass index (BMI) [weight (kg) / height (m)2] was used to determine obesity among the study population. The subjects were classified into two levels, non-obese, which included those who had BMI less than 25, and obese, which included those who had BMI equal to or more than 25 as described by Garrow9.

Data were stored on a D-Base file and the SPSS software package was used for data management and analysis.

RESULTS

Means and standard deviations of BMI according to social and lifestyle factors of adult Bahrainis are shown in Table 1.  There was a significant difference in mean BMI between men and women in all factors studied, and women had a higher mean BMI than men.  This finding suggests that women were heavier than men.  When the mean BMI was compared within each sex, a significant difference was found in mean BMI with age, education, smoking, history of hypertension and watching television.  The mean BMI for currently married men was lower than that for unmarried men (26.3 and 27.8, respectively).  However, this trend was not observed among women, as the mean BMI was almost equal in both groups (30.1 and 30.0, respectively).  Women with diabetes had a higher mean BMI (31.7) than non-diabetic women (29.9) and the difference was statistically significant.  Among men, the mean BMI was similar for both diabetics and non-diabetics (26.4 and 26.1, respectively).

Table 1.  Social and lifestyle factors of Bahraini adults (30-79 years) by mean and standard

The relationship between the weight status of Bahraini adults and social, lifestyle and health factors is given in Table 2.  Obesity was more prevalent among younger adults (<50 years), female, unmarried, non-smokers, hypertensive, diabetic and those who watched television daily.  With the exception of marital status, the association between weight status and these factors was statistically significant.  Overweight was more prevalent among high education subjects (44.4%), compared to low (29.8%) and middle education (34.2%) subjects.  However, the proportion of obesity among the three education groups was almost the same.  The association between education and weight status was statistically significant (p=0.040).

Table 2.  Social, health and lifestyle factors associated with weight status of adult Bahraini adults
 

DISCUSSION

Two important findings were obtained from this study.  First, the weight status of adult Bahraini is highly associated with social, lifestyle and health factors, which indicates that the causes of obesity are multi-factorial.  Second, women showed a higher BMI than men, with the result that obesity is more prevalent in adult females than males.  The prevalence of overweight was slightly higher among men (35.5%) than women (31.3%).  In contrast, women showed about double the proportion of obesity compared to men (48.4% and 21%).  These data supported those reported in other Gulf countries, as obesity was determined by several factors and women were more prone to be obese than men10,11.

Older people (>50 years) showed a lower proportion of obesity than younger people (<50 years).  The phenomena that obesity increased with age until the age of 50 or 60 years was demonstrated by other investigators in the Gulf region11,12.  The age-related increase in obesity during young adulthood and middle age is not only a consequence of slowly accumulating excess of fat, it is also likely to be promoted by the fact that most people reduce the frequency, duration and intensity of physical activity very considerably as they age13.

Interestingly, high education level had a higher percentage of overweight compared to other education groups.  This result is in line with that found in the United Arab Emirates, as overweight and obesity were more prevalent among university educated than non-university educated men14.  In contrast, Khashoggi et al15 showed that obesity was lower among high education Saudi women followed by low and middle education, respectively. Education, is mostly linked with age, and probably in our study older people were also low educated, and this may explain the lower prevalence of obesity among the low education subjects.

A significant difference in obesity was observed between smokers and non-smokers, as the latter group were more susceptible to obesity. Studies on the relationship between smoking and obesity were inconclusive.  However, a number of studies have shown that cigarette smokers weigh less than non-smokers and are less likely to be overweight than non-smokers.  In a multiple regression analysis that adjusted for age, alcohol consumption and physical activity, both male and female smokers had a lower mean BMI than people who had never smoked13.

Hypertension and diabetes were highly statistically associated with weight status in our subjects.  The main cause of excess mortality among obese people is heart disease and hypertension.  In women, obesity (following age and blood pressure) is the third most powerful predicator of heart disease.  In epidemiological studies the prevalence of diabetes increases with increasing severity as well as duration of obesity.  However, diabetes is not directly the cause of most of the excess mortality among obese people.  The metabolic defect underlying non-insulin diabetes mellitus is clearly the result of obesity, which itself predisposes to hypertension and heart disease13.

Hours of watching television had a significant association with weight status (p=0.0364).  The percentage of obesity among people who watched television daily (34.5%) was higher than those who rarely or occasionally watched television (23.9%), but the proportion of overweight was the same in both groups (34.1% and 33.0%, respectively).  Studies on the association of television with obesity are not consistent16,17.  Some researchers suggested that the food eaten during watching television may be a confounding factor for obesity, as most of these foods are high in fat and energy.  Further investigations on the relationship between watching television and obesity are needed, especially in our region where the television plays an important role in leisure time activity in both children and adults.

CONCLUSION

In conclusion, the present study confirmed the findings of other studies in the region as well as in western countries, that obesity is highly prevalent in the community and is caused by several social and lifestyle factors.  Dietary patterns, although not studied, is another contributing factor.  These findings suggest that the health authority in the country should establish a programme to prevent and control obesity as it is one of the main factors linked with occurrence of chronic non-communicable diseases.  To be effective, such a programme should take into consideration the socio-economic status, dietary habits, and cultural factors that are associated with obesity in the Bahraini community.

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