Food insecurity, food choices, and body mass index in adults: nutrition transition in Trinidad and Tobago

Martin C Gulliford, Deepak Mahabir and Brian Rocke

Department of Public Health Sciences, King’s College London, Nutrition and Metabolism Division, Ministry of Health, Laventille, Trinidad and Tobago.

Correspondence: Martin Gulliford, Department of Public Health Sciences, King’s College London, Capital House, 42 Weston St, London SE1 3QD, UK. E-Mail: martin.gulliford{at}kcl.ac.uk


    Abstract
 Top
 Abstract
 Methods
 Results
 Discussion
 Conclusions
 References
 
Background This study evaluated whether food insecurity and obesity were associated in a population sample in Trinidad.

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 24–89) 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: 0.36–0.99, P = 0.045) or green vegetables or salads (food insecure 28%, food secure 51%; adjusted OR = 0.46, 95% CI: 0.27–0.79, P = 0.005) on >=5–6 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 25–29 kg/m2, and 120 (26%) had BMI >=30 kg/m2. Underweight (OR = 3.21, 95% CI: 1.17–8.81) was associated with food insecurity, but obesity was not (OR = 1.08, 95% CI: 0.55–2.12).

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.


Keywords Obesity, body mass index, food insecurity, socioeconomic status, food intake, Trinidad and Tobago, West Indies

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 1997–1999.15 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
 Top
 Abstract
 Methods
 Results
 Discussion
 Conclusions
 References
 
Sample and subjects
We took a sample of approximately 300 households based on the resources available for the survey. The sample was drawn by the Central Statistical Office. The target area was one of the constituencies in north central Trinidad which was considered to provide a good representation of the ethnic and socioeconomic characteristics of the population of Trinidad and Tobago. The area includes a range of settings from a relatively affluent residential suburb of the capital, to areas with small houses on the lower slopes of the northern range characterized by poverty and overcrowding. The area has traditionally been involved in agriculture including market gardening, but this has declined as residential areas spread. There are also good numbers of fruit trees (mango, citrus etc.). A two-stage sampling procedure was used. At the first stage, 15 out of the 66 enumeration districts (ED) in the constituency were selected. This was done by ranking the ED according to size (number of households) then, after a random start, ED were systematically selected. At the second stage, a cluster of approximately 20 households was randomly selected from the clusters in each ED. The fieldworkers visited each household, enumerated all adults, and invited adults aged >=25 years to participate in the survey. The study received research ethics committee approval and subjects gave written informed consent to participation.

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, 5–6 days a week, 3–4 days a week, 1–2 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 >=5–6 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
 Top
 Abstract
 Methods
 Results
 Discussion
 Conclusions
 References
 
There were approximately 300 households listed, and 631 adults aged >=25 years were enumerated. Questionnaire data were obtained for 548 (87%) subjects. Among the 15 clusters, the response rates ranged between 56% and 100% with middle class areas giving lower response rates. Measurements were obtained for 482 (76%) subjects. Two subjects for whom data were collected were aged 23.8 and 24.8 years respectively but these were included in the analyses. The mean age was 46.8 years (SD 14.1 years, range 23.8–89.1 years). There were 250 men and 298 women. The ICC for food insecurity was 0.60 at household level and 0.14 at cluster level. Ethnicity (ICC = 0.36) and household income (ICC = 0.13) were also correlated within clusters of households.

Table 1Go 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.


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Table 1 Responses to individual items on the Household Food Security Scale
 
Table 2Go shows the prevalence of food insecurity according to demographic, socioeconomic, and household characteristics. Odds ratios (OR) were estimated after adjusting for age, gender, and ethnic group. Food insecurity was not associated with age or gender, but subjects of Indo-Trinidadian ethnicity were less likely to be food insecure than Afro-Trinidadians in this sample. This difference remained after additional adjustment for household income (OR = 0.25, 95% CI: 0.13–0.49). After adjusting for age, sex, and ethnicity, there was a strong negative association between household income and food insecurity (test for trend P < 0.001). Food insecurity was strongly associated with the presence of physical limitation (P = 0.001). This association was not explained by adjusting for income, in addition to age sex and ethnic group (adjusted OR = 3.12, 95% CI: 1.55–6.27). There was evidence of a negative association between increasing educational attainment and food insecurity (test for trend, P = 0.005). However, food insecurity was not associated with employment status, the type of water supply in the home, or whether the head of household was male or female. There was little evidence of a trend towards increasing food insecurity with increasing number of children in the family (P = 0.176).


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Table 2 Distribution of food insecurity according to social and demographic factors. Figures are frequency (percentage)
 
Subjects who were food insecure were less likely to be frequent consumers of fruit or green vegetables or salads (Table 3Go). The single item of the HFSS to which affirmative responses were given most frequently was in response to the statement ‘We couldn’t afford to eat balanced meals’. Table 4Go shows the association between this item and frequent consumption of fruit or vegetables. There was evidence of a trend to less frequent consumption of fruit and vegetables with decreasing ability to afford balanced meals. There were no differences according to food insecurity for consumption of rice, bread, legumes, fish, confectionery, or ‘fast foods’ (Table 3Go). Subjects who were food insecure tended to be more likely to eat ‘ground provisions’ (yam, cassava, potatoes, dasheen, edoes etc.) at least weekly. There were no differences in smoking habits or recreational exercise habits according to food security but the food insecure were more likely to report that they were ‘quite inactive’ in terms of non-recreational activity. However, this association was mostly accounted for by additionally adjusting for physical limitation (adjusted OR = 1.81, 95% CI: 0.79–4.14, P = 0.162).


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Table 3 Food choices, smoking, and exercise habits according to level of food insecurity. Figures are frequency (percentage)
 

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Table 4 Consumption of fruit and vegetables in relation to whether subjects could afford to eat balanced meals. Figures are frequency (percentage)
 
Table 5Go shows the mean values for anthropometric variables according to food insecurity for men and women, after adjusting for age and ethnicity. In the food insecure group mean weights and heights tended to be slightly lower, but this was only confirmed statistically for height in women. The distribution of the sample by BMI category is shown in Table 6Go. Overall, 55% of men and 62% of women were overweight or obese, and 21% of men and 29% of women were obese. The distribution of food insecurity according to BMI category is shown in Table 7Go. Food insecurity was common at all levels of BMI. However, the lowest frequency of food insecurity was at intermediate BMI levels (BMI 20.0–24.9 kg/m2 in women and 25.0–29.9 kg/m2 in men). After adjusting for age, gender, and ethnicity, compared with those of normal BMI, the relative odds of being underweight were higher for those who were food insecure (Table 8Go). However, food insecurity was not associated with an increased relative odds of overweight or obesity. There was no statistical evidence for an interaction between gender and BMI group in their association with food insecurity. There was no clear association between household income and BMI category (Tables 7 and 8GoGo).


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Table 5 Mean values (standard error) for anthropometric variables adjusted for age and ethnicity, by sex and food security
 

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Table 6 Distribution of body mass index category by gender. Figures are frequency (percentage)
 

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Table 7 Distribution of food insecurity and household income according to body mass index category. Figures are frequency (percentage)
 

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Table 8 Relative odds of under- or overweight in relation to food insecurity and household income. Figures are odds ratios (95% CI) for body mass index (BMI) category compared with normal weight (BMI 20.0–24.9 kg/m2)
 

    Discussion
 Top
 Abstract
 Methods
 Results
 Discussion
 Conclusions
 References
 
At the community level, food insecurity and obesity were common and often coexisted. At the level of the household and individual, low income and physical limitation were strongly associated with food insecurity. The economic situation of a substantial minority of households appeared to restrict their food choices. Consistent with this, 31% of the sample reported that they ‘sometimes’ or ‘often’ could not afford to eat balanced meals and food insecurity was associated with lower consumption of green vegetables and salads. This hypothesis that food insecurity and obesity might be associated was not supported in these cross-sectional data because food insecurity was common at every level of BMI, and there was no clear association between food insecurity and obesity.

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
 Top
 Abstract
 Methods
 Results
 Discussion
 Conclusions
 References
 
In Trinidad, food insecurity was common in association with low income and physical limitation. There was evidence that subjects who were food insecure, or who were unable to afford to eat a balanced diet, were less likely to consume fruits and vegetables or salads frequently. Overweight and obesity were frequent in all groups but there were no clear associations between either food insecurity, or household income, and obesity.

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

  • Obesity is increasing in middle-income countries but the reasons for the increase are not fully understood.
  • Some studies from high-income countries have suggested that food insecurity may be associated with obesity.
  • We evaluated food insecurity and body mass index in a population sample of adults in Trinidad and Tobago.
  • In this sample, 25% of subjects were food insecure and 60% were overweight or obese. Compared with food secure subjects, people who were food insecure showed an increased relative risk of underweight, but food insecurity was as frequent in those of normal weight as in those who were overweight or obese.
  • Food insecurity was associated with underweight but not with present obesity in these cross-sectional data.

 


    Acknowledgments
 
The authors thank the Chief Medical Officer of Trinidad and Tobago for permission to report this work. We also thank the staff of the Central Statistical Office for help in drawing the sample and for advice on conducting the survey, the Principal Medical Officer (Community Services), and the staff of the Nutrition Division for their skill and dedication in working on the survey.


    References
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 Methods
 Results
 Discussion
 Conclusions
 References
 
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