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Household food insecurity constrains food selection, but whether the dietary compromises associated with this problem heighten the risk of nutrient inadequacies is unclear. The objectives of this study were to examine the relationship between household food security status and adults' and children's dietary intakes and to estimate the prevalence of nutrient inadequacies among adults and children, differentiating by household food security status. We analyzed 24-h recall and household food security data for persons aged 1-70 y from the 2004 Canadian Community Health Survey (cycle 2.2). The relationship between adults' and children's nutrient and food intakes and household food security status was assessed using regression analysis. Estimates of the prevalence of inadequate nutrient intakes by food security status and age/sex group were calculated using probability assessment methods. Poorer dietary intakes were observed among adolescents and adults in food-insecure households and many of the differences by food security status persisted after accounting for potential confounders in multivariate analyses. Higher estimated prevalences of nutrient inadequacy were apparent among adolescents and adults in food-insecure households, with the differences most marked for protein, vitamin A, thiamin, riboflavin, vitamin B-6, folate, vitamin B-12, magnesium, phosphorus, and zinc. Among children, few differences in dietary intakes by household food security status were apparent and there was little indication of nutrient inadequacy. This study indicates that for adults and, to some degree, adolescents, food insecurity is associated with inadequate nutrient intakes. These findings highlight the need for concerted public policy responses to ameliorate household food insecurity.

Discussion

Household food insecurity was associated with the consumption of poorer quality diets among adults, as indicated by systematically lower nutrient intakes and the consumption of fewer servings of milk products, fruits and vegetables, and in some cases, meat and meat alternates. These findings are consistent with previous U.S. research (11-13,19) demonstrating that household food insecurity is associated with dietary compromise for adults and are corroborated by U.S. studies documenting lower serum nutrient concentrations among adults in households characterized by food insecurity (37) or food insufficiency (13).

We noted few differences in young children's nutrient intakes in relation to household food security status, but those in foodinsecure subgroups consumed fewer servings of fruits and vegetables and milk products, suggesting some constraints on their food intakes. Among older children in food-insecure households, there were some indications of lower nutrient intakes. A notable finding among children is the positive association between household food insecurity and energy density among some subgroups, which could impact weight status over time if household food insecurity and its associated dietary patterns are chronic experiences.

Although the inclusion of potentially confounding covariates attenuated the effect of household food insecurity on intakes of some nutrients, a number of effects of household food security status remained significant. One possible explanation for the loss of significance, particularly in the analyses for women 19-30 y, is the strong correlation between food insecurity and other independent variables in the model (most notably income adequacy and education). This situation, known as colinearity, can result in a loss of significance for individual parameters by inflating the estimated variances of the regression coefficients (38).

Substantial prevalences of inadequacy were observed for adults in food-insecure households across a wide spectrum of nutrients. Adolescents in food-insecure households also had relatively high prevalences of inadequacy for some nutrients, notably vitamin A, protein, and magnesium. In almost all cases where a prevalence of inadequacy in excess of 10% was observed, the prevalence was higher among those in food-insecure households. These results suggest that compromises in dietary intakes in the context of household food insecurity are of sufficient gravity to heighten the vulnerability of some age/sex groups to nutrient inadequacies. Our examination of prevalences of nutrient inadequacies extends the understanding of nutritional vulnerability that can be gleaned from the results of group mean comparisons. Even though food or nutrient intakes may differ significantly by household food security status, it does not necessarily follow that the usual intakes of those in food-insecure households are so low as to be associated with increased risk of nutrient inadequacies, and the reverse is also true. For example, women 51-70 y in foodinsecure households had more than twice the prevalence of inadequacy for vitamin B-6 of women in food-secure households, but no difference in group means was observed.

We have not applied statistical tests to compare estimates of prevalence of nutrient inadequacies between food-secure and -insecure groups. The degree of overlap of the CI around the estimates for the food-secure and food-insecure subgroups for each age/sex group provides some indication of the extent to which differences are significant. However, the standard errors and resulting CI are underestimates of the true error associated with the prevalence estimates due to the effect of the clustering in the survey design and the variability associated with both the EAR and the collection of dietary intake data (16). Our examination of nutrient inadequacies is also limited by the small numbers of respondents in food-insecure households in some age/sex groups and the smaller numbers of replicate 24-h recalls for respondents in these groups. The instability of estimates derived from samples with insufficient replicates is highlighted by the extraordinarily wide CI around prevalence estimates for some nutrients for some subgroups. There are some indications that individuals' intakes are sensitive to perturbations in household resources (39,40), suggesting that a greater number of replicate observations is likely required to obtain a stable estimate of within-person variation among groups whose dietary intakes are affected by household food insecurity. Without oversampling of population subgroups vulnerable to household food insecurity and/or the completion of replicate 24-h recalls by a larger proportion of survey samples, it is impossible to overcome this limitation.

Problems of underreporting are ubiquitous in dietary intake surveys (16) and CCHS 2.2 is likely no exception. In this study, we used the EI:EER ratio to assess reporting quality, recognizing that EI:EER does not provide an indication of the quality of data for nutrients. Although this assessment was limited by the lack of physical activity data at the level of detail specified in the DRI energy report (30) and the absence of measured height and weight values for some respondents, the mean ratios were < 1 for all adult and adolescent subgroups, suggesting underreporting. Whereas differences observed in mean intakes and prevalences of inadequacy might be attributable to a greater degree of underreporting among respondents in food-insecure households, EI:EER differed significantly in relation to food security status in only 2 subgroups (females 19-30 y and 51-70 y). These differences might indicate greater underreporting among women in food-insecure households, but they may also be a reflection of the food compromises associated with food insecurity (17). This is implied for females 51-70 y by the significantly lower intakes of fruit and vegetables, milk products, and meat and alternates and the high prevalence of inadequacy noted across a spectrum of micronutrients.

We did not observe differences in EI:EER by food security status among children (except for the positive association with food insecurity among 4-8 y olds after adjusting for potential confounders) and the mean values for those aged 4-13 y do not suggest substantial under- or overreporting of EI. However, we were unable to differentiate children's activity levels. Thus, EER was underestimated and EI:EER overestimated for children with more than sedentary levels of activity, making it difficult to gauge the quality of energy reporting for these subgroups. Although reporting problems may explain why more differences were not found in children's nutrient intakes, an alternate explanation lies in the continuum of food insecurity whereby the quality and quantity of adults' intakes are typically affected before children's intakes are compromised (21,23,24).

This study indicates that the phenomenon of food insecurity, measured routinely in population surveys in both Canada and the US, is a marker of dietary compromises among adults and adolescents that are of sufficient magnitude to heighten risk of nutrient inadequacies. The nutritional vulnerability associated with food insecurity highlights the urgent need for policy responses to address the root causes. Further, the poorer dietary intakes observed among Canadians living in food-insecure households are particularly worrisome if they represent long-term dietary patterns, speaking to the need for longitudinal research to elucidate the chronicity of food insecurity and its nutritional consequences.