Department of Public Health Sciences, Kings College London, Nutrition and Metabolism Division, Ministry of Health, Laventille, Trinidad and Tobago.
Correspondence: Martin Gulliford, Department of Public Health Sciences, Kings College London, Capital House, 42 Weston St, London SE1 3QD, UK. E-Mail: martin.gulliford{at}kcl.ac.uk
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Methods A sample was drawn of 15 clusters of households, in north central Trinidad. Resident adults were enumerated. A questionnaire was administered including the short form Household Food Security Scale (HFSS). Heights and weights were measured. Analyses were adjusted for age, sex, and ethnic group.
Results Data were analysed for 531/631 (84%) of eligible respondents including 241 men and 290 women with a mean age of 47 (range 2489) years. Overall, 134 (25%) of subjects were classified as food insecure. Food insecurity was associated with lower household incomes and physical disability. Food insecure subjects were less likely to eat fruit (food insecure 40%, food secure 55%; adjusted odds ratio [OR] = 0.60, 95% CI: 0.360.99, P = 0.045) or green vegetables or salads (food insecure 28%, food secure 51%; adjusted OR = 0.46, 95% CI: 0.270.79, P = 0.005) on 56 days per week. Body mass index (BMI) was available for 467 (74%) subjects of whom 41 (9%) had BMI <20 kg/m2, 157 (34%) had BMI 2529 kg/m2, and 120 (26%) had BMI
30 kg/m2. Underweight (OR = 3.21, 95% CI: 1.178.81) was associated with food insecurity, but obesity was not (OR = 1.08, 95% CI: 0.552.12).
Conclusions Food insecurity was frequent at all levels of BMI and was associated with lower consumption of fruit and vegetables. Food insecurity was associated with underweight but not with present obesity.
Accepted 3 December 2002
The health transition in middle-income countries is associated with falling mortality rates and the emergence of non-communicable diseases as the main causes of death.1 As the importance of undernutrition declines, obesity has emerged as a significant public health problem.2,3 The reasons for the increase in obesity are not fully understood but decreasing levels of physical activity and increasing availability of foods high in fat or refined carbohydrate are thought to be important contributing factors.3,4
In low-income countries, obesity is associated with affluence but in high-income countries obesity is more often associated with lower socioeconomic status.5 This observation suggests that, in a more food-abundant environment, socioeconomic factors such as education and income level may modify the relationship between food availability and obesity. In the middle-income countries, these relationships are less consistent. Obesity may be associated with affluence in some situations but with poverty in others.6 Underweight and obesity may sometimes co-exist in the same neighbourhoods,7 or even in the same households.8 These findings suggest an apparent paradox that obesity may exist in households that are food insecure.9 It has been suggested that limited availability of food may lead to obesity.9 This might occur if food insecurity leads to the consumption of obesity promoting types of food,9 or to overeating when food becomes available, or to metabolic changes that permit more efficient use of energy.10
Food insecurity has been defined as the limited or uncertain availability of nutritionally adequate and safe foods, or limited or uncertain ability to acquire acceptable foods in socially acceptable ways.11 The concept of food insecurity includes problems with the quantity and quality of the food available, uncertainty about the supply of food, and experiences of going hungry.12 Blumberg et al.13 recently described a short form of the Household Food Security Scale (HFSS) which includes six items. These concern experiences of cutting the size of meals or skipping meals because of lack of money for food, being hungry but not eating because of an inability to afford food, food not lasting and not having enough money to buy more, and being unable to afford balanced meals. According to this instrument, respondents are classified as food insecure if they give affirmative responses to two of the six items.
In the Caribbean region in 2000, the per capita GNP of the English speaking countries ranged from US$2440 in Jamaica to US$4980 in Trinidad and Tobago and US$9280 in Barbados.14 These figures contrast with values of US$24 500 in the UK and US$34 260 in the USA.14 Food security continues to be a significant concern for public policy in the Caribbean. According to the UN Food and Agriculture Organization, 13% of the Trinidad and Tobago population were undernourished in 19971999.15 Most attention has been directed at the nutritional status of children and the need to provide meals in school to increase dietary intakes in order to improve nutritional and educational outcomes.16,17 However, in children in Trinidad and Tobago, overweight, as well as underweight, appears to be prevalent.18 Obesity in adults is also important in the Caribbean region. Beckles et al. found that between 27% and 32% of women in Port of Spain, Trinidad were obese.19 Rotimi et al. found that the prevalence of obesity in populations of West African descent increased with increasing economic development. Using the criterion of body mass index (BMI) 31.1 kg/m2 for men and BMI
32.3 kg/m2 for women, the prevalence of obesity was 10.3% in men and 30.1% in women in Barbados.20
In the Eastern Caribbean, a study of the relationship between food insecurity and BMI in adults is both relevant and feasible because both conditions are likely to be common. We carried out a population survey in Trinidad with the aim of evaluating the prevalence of both food insecurity and obesity, and the relationship between them. We evaluated associations of food insecurity with general health, food choices, physical activity levels, and socioeconomic status.
![]() |
Methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Questionnaire
Subjects were asked to complete an interview-administered questionnaire. This included items on food choices, food security, cigarette smoking, alcohol use, physical activity, general health, and socioeconomic variables. The questionnaire was administered by trained interviewers who usually work on surveys for the Central Statistical Office. Many of the questionnaire items were adapted, with permission, from the report of the Health Survey for England 1994.21
The short form of the HFSS was included as described by Blumberg et al.13 This instrument is also referred to as the food security core module.22 We found that the six items were readily understood in face-to-face interviews. A short food frequency questionnaire was included. Subjects were asked how often they ate the following groups of foods: sweet biscuits or cake; fruit; green vegetables and salads; fish (including shellfish); sweets or chocolate; burgers, fried chicken or pizzas; beans, peas lentils etc.; ground provisions including yam, cassava, potatoes, dasheen, edoes etc.; roti; and rice. Categories used were more than once a day, once every day, 56 days a week, 34 days a week, 12 days a week, at least once a month, less than once a month, rarely or never. For analysis, for foods that were consumed frequently the categories were reduced to eaten 56 days a week or not, and for less frequently consumed foods, categories were reduced to eaten at least weekly or not. Cigarette smoking was analysed using the categories non-smoker, ex-smoker, and current smoker. Physical activity levels were analysed using two global questions from the NHANES I study:23 Do you get much exercise in things you do for recreation (sport, walking for exercise, anything like that) or hardly any exercise or in between? and In your usual day, aside from recreation are you physically very active, moderately active or quite inactive? Responses to these questions were strongly associated with more detailed questions concerning recreational, work, and household activities. The questionnaire included the following item concerning physical limitation from the SF12: During the last 4 weeks, were you limited in the kind of work or other regular daily activities you do, as a result of your physical health?24 Subjects were also asked about the monthly income of their household using ten categories ranging from
TT$200 (US$33.3) to
TT$51 201 (US$8533.5). For analysis the lowest three, and highest four, categories were combined. Subjects were asked How would you describe your ethnic group? Responses were classified into the categories, African, Indian, white, Chinese, mixed, other, or not known. This represented a shortened form of the categories used in the Trinidad and Tobago national census.25 For analysis the categories were further reduced to Afro-Trinidadian, Indo-Trinidadian, Mixed, and Other and not known. Subjects were also asked about the water supply in the home, whether the head of the household was male or female, the number of adults and children in the home, their personal educational attainment, and employment status, as described previously.18
Measurements
Measurements of height and weight were taken by the nutritionists and food demonstrators from the Nutrition Division of the Ministry of Health. The measurement procedures generally followed those used in the Health Survey for England 1994.21 Height was measured using a portable stadiometer (Seca Leicester height pole). Values were recorded to the last complete 0.1 cm and 0.05 cm was added at the time of analysis to correct the bias. Weight was measured using portable electronic scales (Soehnle) to the nearest 0.1 kg. Waist and hip circumferences were measured using tape measures.
The waist was defined as the midpoint between the lower rib margin and the iliac crest, and the hips as the maximum circumference over the buttocks.21 Two measurements were made but if these two measurements differed by >2 cm then a third measurement was taken. Subjects were measured in light clothing but without shoes. Fieldworkers also noted whether there was any difficulty recording any of the measurements.
Analysis
For these analyses, age was taken as the difference between the date of birth and the measurement date. For 11 cases where date of birth not available, the reported age last birthday plus one half was used. Underweight was defined as a BMI <20 kg/m2. Overweight was defined as BMI 25 kg/m2 and obesity as BMI
30 kg/m2. In order to allow for the sampling design, random effects logistic regression models were fitted using the statistical package MLwiN version 1.10.26,27 A three-level model was specified with individuals nested within households, and households within clusters of households. Logistic regression models were fitted using first order maximum quasi-likelihood estimation because penalized quasi-likelihood estimation did not lead to convergence.26 P-values were obtained by comparing the coefficient with its standard error in the three-level model. Intraclass correlation coefficients (ICC) were estimated by restricted maximum likelihood. The ICC at household level were estimated allowing for the effect of cluster of households. Adjusted means were obtained from a random effects model allowing for clustering by household only, using the xtreg command with the maximum likelihood option in Stata.28
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Table 1 shows the responses obtained for the six items of the HFSS, together with the distribution of summed affirmative responses. Of the 548 respondents, 17 had missing data for all items on the HFSS. These cases were excluded, and the remaining analyses were confined to 531 (84%) of subjects with data for food security with measurements available for 467 (74% total). Of these, 134 (25%) were classified as being food insecure. Among 77 subjects with missing values for income, 7 (9%) were food insecure compared with 127/454 (28%) with known income levels. In 64 subjects with missing values for BMI, 10 (16%) were food insecure compared with 124/467 (27) with known BMI.
|
|
|
|
|
|
|
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Limitations of study
The main limitation of the study related to the size and structure of the sample. We aimed to sample an area that could be considered typical of the socioeconomic conditions of Trinidad and Tobago. However, compared with previous national studies, this sample included a higher proportion with university education and a lower proportion without piped water supply in the home.18 The overall response rate was satisfactory but the response rate tended to be somewhat lower in more affluent areas which could have positively biased the assessment of the prevalence of food insecurity. In addition, data for household income were not obtained for 16%, and BMI for 24%, of initial responders. The strengths of the survey were the carefully standardized instruments which were administered by trained staff. The HFSS has been extensively studied in the US.29 As Trinidad and Tobago is an English speaking country, we used the scale without modification in order to allow comparability of results. We did not attempt to specifically evaluate the questionnaire for use in Trinidad and Tobago. However, the unexplained ethnic differences in food insecurity might raise the possibility of cultural differences in response to this instrument.
Comparison with other work
Survey data suggest that up to 12% of US households may experience some food insecurity,11 although a smaller proportion experience food insecurity with hunger.11,12 Recent studies have associated food insecurity with BMI. Olson reported analyses of data for 193 women living in rural locations in New York state. She found that the mean BMI of women living in food insecure households was higher than for women living in food secure households. Only for women with severe food insecurity was BMI lower than for the food secure.30 In a nationally representative sample of 6506 men and women in Finland, Sarlio-Lahteenkorva and Lahelma found that thin people showed the most food insecurity but obese subjects reported fearing or experiencing running out of money for food, and buying cheaper foods because of financial restrictions more frequently than subjects with normal BMI.31 In data from a national US survey of food intakes, Townsend et al. found an association between food insecurity and overweight in women but not men.32 Alaimo et al.10 found that food insufficiency was associated with overweight in older white US girls but not in African American or Mexican American children. These studies provide preliminary evidence that food insecurity may be surprisingly frequent in high-income countries, and may be associated either with thinness or with obesity. Our results suggest that food insecurity may be more frequent in the setting of a middle-income country.
In a study from the US, Casey et al.,33 found that children from low-income food insufficient families consumed less fruit. Tarasuk34 found that Canadian women from food insecure households reported lower consumption of vegetables, fruit, and meat than women from food secure households. Kendall et al.35 reported decreasing consumption of fruit and vegetables with increasing food insecurity in a rural area in New York state. These observations are consistent with our data which showed that subjects who were food insecure were less likely to eat fruit or vegetables and salads frequently.
In a study from Argentina, Aguirre observed that consumption of fruit and vegetables accounted for 19% of food consumption among the highest income quintile but 14% in the lowest income quintile.36 She noted that the price of 500 g lettuce would buy 700 g beef or 1.5 kg of pasta or 1.4 kg of bread. The price structure of food appeared to promote the consumption of foods with higher energy content. Consumption of vegetables has been negatively associated with obesity in some studies.37 Bell and Rolls found that in women, consumption of energy dense foods gave a 20% higher energy intake but with similar ratings for hunger or fullness.38 Data from NHANESIII showed that consumption of energy-dense nutrient-poor foods accounted for higher energy intakes and reduced compliance with dietary recommendations.39
Physical limitations may prevent people gaining access to food both directly by reducing their ability to acquire food, and indirectly by influencing their ability to work and obtain income. Our results showed a strong association between food insecurity and physical limitation. Physical limitations also accounted for the lower levels of physical activity among those who were food insecure. It was difficult to account for the marked ethnic difference observed for food insecurity, which was not explained by differences in household income. It is possible that there are cultural differences in perception and reporting of food insecurity, and this possibility makes the application of more objective measures of food supply desirable.
Nutrition transition
Our results show that even in a relatively affluent middle-income country perceptions of food insecurity may be widespread, especially among those on low incomes, but at the same time obesity is also an important problem. Middle income countries are considered to be engaged in a process of nutrition transition40 through which widespread under-nutrition is gradually replaced by a situation in which dietary intakes and physical activity patterns predispose to the development of obesity and associated non-communicable disorders. Current economic policies aim to promote economic development and thus reduce the conditions in which food insecurity is found. However, liberalization of trade may have the effect of increasing the importation of processed foods, or used cars, thereby perhaps contributing to the development of obesity. Popkin40 has observed that key questions concern how potentially unfavourable health outcomes of these processes may be avoided, prevented, or reversed.
![]() |
Conclusions |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Any relationship between food security and obesity is likely to evolve over time. Future studies might therefore use prospective designs at key stages of the life course, in order to provide further insights into these relationships, which appear to be particularly relevant in middle-income country settings.
KEY MESSAGES
|
![]() |
Acknowledgments |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
2 Popkin BM. The nutrition transition and obesity in the developing world. J Nutr 2001;131:871S73S.
3 World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation. WHO Technical Report Series No. 894. Geneva: World Health Organization, 2000.
4 Harnack LJ, Jeffrey RW, Boutelle KN. Temporal trends in energy intake in the United States: an ecologic perspective. Am J Clin Nutr 2002;71:147884.
5 Sobal J, Stunkard AJ. Socioeconomic status and obesity: a review of the literature. Psychol Bull 1989;105:26075.[CrossRef][ISI][Medline]
6 Monteiro CA, Conde WL, Popkin BM. Independent effects of income and education on the risk of obesity in the Brazilian adult population. J Nutr 2001;131:881S86S.
7 Doak CM, Adair LS, Monteiro C, Popkin BM. Overweight and underweight coexist within households in Brazil, China and Russia. J Nutr 2000;130:296571.
8 Florencio TM, Ferreira HS, de Franca AP, Cavalcante JC, Sawaya AL. Obesity and undernutrition in a very-low-income population in the city of Maceio, northeastern Brazil. Br J Nutr 2001;86:27784.[ISI][Medline]
9 Dietz WH. Does hunger cause obesity? Pediatrics 1995;95:76667.[ISI][Medline]
10 Alaimo K, Olson CM, Frongillo EA Jr. Low family income and food insufficiency in relation to overweight in US children: is there a paradox? Arch Pediatr Adolesc Med 2001;155:116167.
11 Carlson SJ, Andrews MS, Bickel GW. Measuring food insecurity and hunger in the United States: Development of a national benchmark measure and prevalence estimates. J Nutr 1999;129:510S06S.[ISI][Medline]
12 Alaimo K, Briefel RR, Frongillo EA Jr, Olson CM. Food insufficiency exists in the United States: results from the third National Health and Nutrition Examination Survey (NHANES III). Am J Public Health 1998; 88:41926.[Abstract]
13 Blumberg SJ, Bialostosky K, Hamilton WL, Briefel RR. The effectiveness of a short form of the Household Food Security Scale. Am J Public Health 1999;89:123134.[Abstract]
14 World Bank. World Development Indicators Database. Washington: World Bank, 2001.
15 United Nations Food and Agriculture Organization. The state of food security in the world. http://www.fao.org/docrep/003/y1500e/y1500e06.htm#P0_3 accessed 15 April 2002.
16 Walker SP, Powell CA, Hutchinson SE, Chang SM, Grantham-McGregor SM. Schoolchildrens diets and participation in school feeding programmes in Jamaica. Public Health Nutr 1998;1:4349.[Medline]
17 Gulliford MC, Mahabir D, Rocke BC, Chinn S, Rona RJ. Free school meals and childrens social and nutritional status in Trinidad and Tobago. Public Health Nutr 2002;5:62530.[CrossRef][ISI][Medline]
18 Gulliford MC, Mahabir D, Rocke B, Chinn S, and Rona RJ. Overweight, obesity and skinfold thicknesses of children of African or Indian descent in Trinidad and Tobago. Int J Epidemiol 2001;30:98998.
19 Beckles GL, Miller GJ, Alexis SD et al. Obesity in women in an urban Trinidadian community. Prevalence and associated characteristics. Int J Obes 1985;9:12735.[ISI][Medline]
20 Rotimi CN, Cooper RS, Ataman SL et al. Distribution of anthropometric variables and the prevalence of obesity in populations of west African origin: the International Collaborative Study on Hypertension in Blacks (ICSHIB). Obes Res 1995;3(Suppl.2):95S105S.[Abstract]
21 Colhoun H, Prescott-Clarke P. Health Survey for England 1994. London: HMSO, 1996.
22 USDA Food and Nutrition and Economic Research Service. Food security/hunger core module. http://www.ers.usda.gov/briefing/foodsecurity/surveytools/core0699.pdf accessed 19 November 2002.
23 Gillum RF, Mussolino ME, Ingram DD. Physical activity and stroke incidence in women and men. The NHANES I Epidemiologic Follow-up study. Am J Epidemiol 1996;143:86069.[Abstract]
24 Jenkinson C, Layte R. Development and testing of the UK SF-12. J Health Serv Res Policy 1997;2:1418.[Medline]
25 Republic of Trinidad and Tobago. Central Statistical Office. 1990 Population and Housing Census. Vol. 2. Age Structure, Religion, Ethnic Group, Education. Port of Spain: Office of the Prime Minister. Central Statistical Office, 1994.
26 Goldstein H. Multilevel Statistical Models. London: Arnold, 1996.
27 Woodhouse G. Multilevel Modelling Applications. A Guide for Users of MLn. London: Institute of Education, University of London, 1998.
28 Stata Corporation. Stata Reference Manual. Release 7. Vol. 4. Su-Z. College Station, TX: Stata Corporation, 2001.
29 Frongillo EA. Validation of Measures of Food Insecurity and Hunger. J Nutr 1999;129:506.
30 Olson CM. Nutrition and health outcomes associated with food insecurity and hunger. J Nutr 1999;129:521S24S.[ISI][Medline]
31 Sarlio-Lahteenkorva S, Lahelma E. Food insecurity is associated with past and present economic disadvantage and body mass index. J Nutr 2001;131:288084.
32 Townsend MS, Peerson J, Love B, Achterberg C, Murphy SP. Food insecurity is positively related to overweight in women. J Nutr 2001; 131:173845.
33 Casey PH, Szeto K, Lensing S, Bogle M, Weber J. Children in food-insufficient, low-income families: prevalence, health, and nutrition status. Arch Pediatr Adolesc Med 2001;155:50814.
34 Tarasuk VS. Household food insecurity with hunger is associated with womens food intakes, health and household circumstances. J Nutr 2001;131:267076.
35 Kendall A, Olson CM, Frongillo EA. Relationship of hunger and food insecurity to food availability and consumption. J Am Diet Assoc 1996; 96:101924.[CrossRef][ISI][Medline]
36 Aguirre P. Socio-anthropological aspects of obesity in poverty. In: Pena M, Bacallao J (eds). Obesity and Poverty: A New Public Health Challenge. Scientific Publication No. 576, pp. 1122. Washington DC: PAHO/WHO, 2000.
37 Lahti-Koski M, Pietinen P, Heliovaara M, Vartiainen E. Associations of body mass index and obesity with physical activity, food choices, alcohol intake, and smoking in the 19821997 FINRISK studies. Am J Clin Nutr 2002;75:80917.
38 Bell EA, Rolls BJ. Energy density of foods affects energy intake across multiple levels of fat content in lean and obese women. Am J Clin Nutr 2001;73:1018.
39 Kant AK. Consumption of energy-dense, nutrient-poor foods by adult Americans: nutritional and health implications. The Third National Health and Nutrition Examination Survey, 19881994. Am J Clin Nutr 2000;72:92936.
40 Popkin BM. An overview on the nutrition transition and its health implications: The Bellagio meeting. Public Health Nutr 2002;5: 93103.[CrossRef][ISI]