Food trade, food security and health in the Caribbean

Trade and food security are tied together in the Caribbean through a variety of linkages rooted in the importance of exports and imports to their economies. On the one hand, export-oriented economic activity is a major source of foreign exchange and employment-based income-earning opportunities (linked to both the supply and accessibility dimensions of food security). On the other hand imports are equally critical to nutritional and stability dimension of food security, as most of these countries are net food importers. Further , much of the production for national, regional and international trade is dependent on imported inputs, thereby underlining the dynamic synergies between imports, exports and food security. The first section of this paper highlights trade and food security linkages in the Caribbean.

Food trade, food security and health in the Caribbean

Trade and food security are tied together in the Caribbean through a variety of linkages rooted in the importance of exports and imports to their economies. On the one hand, export-oriented economic activity is a major source of foreign exchange and employment-based income-earning opportunities (linked to both the supply and accessibility dimensions of food security). On the other hand imports are equally critical to nutritional and stability dimension of food security, as most of these countries are net food importers. Further , much of the production for national, regional and international trade is dependent on imported inputs, thereby underlining the dynamic synergies between imports, exports and food security. The first section of this paper highlights trade and food security linkages in the Caribbean.

The 18 Household Food Security Survey items provide valid food security classifications for adults and children in the Caribbean

BACKGROUND: We tested the properties of the 18 Household Food Security Survey (HFSS) items, and the validity of the resulting food security classifications, in an English-speaking middle-income country. METHODS: Survey of primary school children in Trinidad and Tobago. Parents completed the HFSS. Responses were analysed for the 10 adult-referenced items and the eight child-referenced items. Item response theory models were fitted. Item calibrations and subject scores from a one-parameter logistic (1PL) model were compared with those from either two-parameter logistic model (2PL) or a model for differential item functioning (DIF) by ethnicity. RESULTS: There were 5219 eligible with 3858 (74%) completing at least one food security item. Adult item calibrations (standard error) in the 1PL model ranged from -4.082 (0.019) for the 'worried food would run out' item to 3.023 (0.042) for 'adults often do not eat for a whole day'. Child item calibrations ranged from -3.715 (0.025) for 'relied on a few kinds of low cost food' to 3.088 (0.039) for 'child didn't eat for a whole day'. Fitting either a 2PL model, which allowed discrimination parameters to vary between items, or a differential item functioning model, which allowed item calibrations to vary between ethnic groups, had little influence on interpretation. The classification based on the adult-referenced items showed that there were 19% of respondents who were food insecure without hunger, 10% food insecure with moderate hunger and 6% food insecure with severe hunger. The classification based on the child-referenced items showed that there were 23% of children who were food insecure without hunger and 9% food insecure with hunger. In both children and adults food insecurity showed a strong, graded association with lower monthly household income (P < 0.001). CONCLUSION: These results support the use of 18 HFSS items to classify food security status of adults or children in an English-speaking country where food insecurity and hunger are more frequent overall than in the US.

Reliability and validity of a short form household food security scale in a Caribbean community

BACKGROUND: We evaluated the reliability and validity of the short form household food security scale in a different setting from the one in which it was developed. METHODS: The scale was interview administered to 531 subjects from 286 households in north central Trinidad in Trinidad and Tobago, West Indies. We evaluated the six items by fitting item response theory models to estimate item thresholds, estimating agreement among respondents in the same households and estimating the slope index of income-related inequality (SII) after adjusting for age, sex and ethnicity. RESULTS: Item-score correlations ranged from 0.52 to 0.79 and Cronbach's alpha was 0.87. Item responses gave within-household correlation coefficients ranging from 0.70 to 0.78. Estimated item thresholds (standard errors) from the Rasch model ranged from -2.027 (0.063) for the 'balanced meal' item to 2.251 (0.116) for the 'hungry' item. The 'balanced meal' item had the lowest threshold in each ethnic group even though there was evidence of differential functioning for this item by ethnicity. Relative thresholds of other items were generally consistent with US data. Estimation of the SII, comparing those at the bottom with those at the top of the income scale, gave relative odds for an affirmative response of 3.77 (95% confidence interval 1.40 to 10.2) for the lowest severity item, and 20.8 (2.67 to 162.5) for highest severity item. Food insecurity was associated with reduced consumption of green vegetables after additionally adjusting for income and education (0.52, 0.28 to 0.96). CONCLUSIONS: The household food security scale gives reliable and valid responses in this setting. Differing relative item thresholds compared with US data do not require alteration to the cut-points for classification of 'food insecurity without hunger' or 'food insecurity with hunger'. The data provide further evidence that re-evaluation of the 'balanced meal' item is required.

Food insecurity definitions and body mass index. Response

In his commentary, Dr Edward A. Frongillo criticizes our use of a well-described household food security scale in Trinidad. There will always be some uncertainty concerning the application of a given measure as there is no perfect instrument to evaluate food security or dietary patterns in any population. The household food security measure was used in the US national Current Population Survey (which provided the comparison data used in Dr Frongillo's commentary) but the application of the instrument to all groups in the multilingual, culturally diverse US population 'has not been examined sufficiently' (ref. 3, p. 8). Questionnaire evaluation must be considered when differences in literacy, language, dialect, or culture, as well as socioeconomic status, may influence responses and this consideration might suggest that an instrument should be tailored to local requirements. It is advisable, however, to be judicious in modifying such measures so as not to compromise the validity or comparability of an instrument. Departures from a previously tested template should only be undertaken to guarantee enhanced performance of a measure. Dr Frongillo's comments appear to underestimate both the weight of evidence required to justify an alteration to an established measure and the limitations of local 'validation' studies. Before concluding that a measure gives unsatisfactory results in a given local population, or a particular group within a population, it is essential to ensure that the findings cannot be ascribed to error or bias. There is a relatively high risk that local questionnaire evaluation studies, implemented within the short time scales suggested, will lead to erroneous conclusions if sample sizes are too small or if subjects are insufficiently representative.

Commentary: Assessing food insecurity in Trinidad and Tobago

Gulliford and colleagues report in this issue of the International Journal of Epidemiology on a study in Trinidad and Tobago that investigated whether household food insecurity was associated with obesity in this middle-income country. They found that food insecurity was associated with underweight but not with obesity. Food insecurity was also associated with decreased consumption of fruits and vegetables, a result previously reported in several studies, and with physical limitations, a result previously reported for elders in the US.

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

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/m(2), 157 (34%) had BMI 25-29 kg/m(2), and 120 (26%) had BMI >/=30 kg/m(2). 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.

Food saftey: an examination of the potential impact on the economies of countries of the Caribbean Community [abstract]

Food safety pertains to the prevention, reduction or elimination of the risk of ill-health as a result of the consumption of foods whether fresh or processed, obtained through the domestic market or by international trade. Food saftey issues therefore impact on agricultural production and trade, as well as on the manufacture of processed foods and on the preparation and service of meals, whether these be in a hotel/restaurant environment or by itinerant street vendors. Agricultural production, trade and tourism are together significant contributors to the output of the open economies of the countries of the Caribbean Community. The discussion examines the findings of a recent assessment of the food safety status of Caribbean Community (CARICOM) Member States, which focussed on food safety in respect of plant, animal and human health systems in the various countries. The economic structure of selected countries is highlighted together with an indication of the trends in trade. The findings of the food safety assessment are then reviewed in the context of their possible impact on the economic output of the countries. The analysis showed that agricultural production and trade play a critical role in the economic output of many CARICOM States, Through their contribution to export earnings as well as employment. Tourism is also important in this regard. Inadequate attention to food safety issues can result in loss of market share either through a shift in purchasing patterns as experienced by other countries, or through detention by the regulatory agency of the importing country. Weak food safety policies could also jeopardize the tourism sector. Improvements in the food safety system and its infrastructure would serve to enhance the earning potential of the agricultural and tourism sectors and this should lead to greater economic output from those sectors. (AU)

Use of food expenditure data to estimate household nutrient accessibility

The nutritional status of at-risk groups is usually monitored using health statistics. This approach has limitations as individuals are identified only after they have been afflicted by morbidity. In Jamaica, national surveys are carried out in which expenditure data on all consumption items are collected. We used these data to monitor food accessibility in at-risk groups. The identification of decreases in accessibility levels relative to requirements would enable timely intervention before there is a deterioration in nutritional status. We analysed the data from the survey of 3861 households conducted by Statistical and Planning Institutes of Jamaica in 1989. Using the food expenditure data, per capita energy and protein accessibility levels were determined. The mean energy and protein accessibility levels for the sample were 2170 Cals and 64 g, respectively. The results showed that the per capita accessibility levels of 20 percent and 9 percent of the households were less than half of requirments for energy and protein, respectively. The situation was worse in rural areas than in urban centres. However, the accessibility levels may have been underestimated as the data did not include meals bought and consumed away from the home, which may be significant to some households. We believe that the use of data from these surveys is a cost-effective way to monitor nutrient accessibility in Jamaica (AU)