The burden of food allergy on children and teens: A systematic review.

BACKGROUND: Over the last two decades, researchers have placed increasing attention on understanding how food allergy affects the health-related quality of life (HRQL) and psychosocial well-being of children and teens. In response, a number of reviews have been published that aim at synthesizing the literature. However, many of these papers focus narrowly on HRQL or suffer from methodological limitations. METHOD: The current review aims to fill this gap by providing a comprehensive overview of the burden of pediatric food allergy by synthesizing the quantitative and qualitative literature. RESULTS: Findings from the present review provide evidence of reduced HRQL among children and teens with food allergy, particularly older children and those with more severe manifestations of the condition. In comparison to HRQL, the link between food allergy and psychosocial functioning is less clear; however, some evidence can be cited linking food allergy to greater levels of psychological distress. Qualitative evidence suggests that the burden of pediatric food allergy largely stems from worries surrounding exposures outside of the home and the social consequences of the condition. The current review also highlights several gaps in the literature, including a paucity of longitudinal research, research focused on predictors of psychological distress among children and teens with food allergy as well as a dearth of studies comparing rates of bullying in food-allergic and non-food-allergic samples. CONCLUSION: More emphasis should be placed on not only alleviating the social and psychological consequences of food allergy, but also on identifying and assisting those most acutely burdened by the condition.

A scoping review of the caregiver burden of pediatric food allergy.

OBJECTIVE: Although a number of articles have described the psychosocial impact of raising a child with a food allergy, recent attempts at synthesizing this literature have been narrow in focus or methodologically limited. Consequently, this study aimed to synthesize both the quantitative and qualitative literature to achieve a better understanding of the psychosocial and financial burdens faced by families who raise children with food allergy. DATA SOURCES: Searches were performed on PubMed, Scopus, PsycInfo, and Cumulative Index to Nursing and Allied Health Literature databases for articles related to the psychosocial and financial burden experienced by individuals who care for a child with food allergy. STUDY SELECTIONS: English language, original research articles were included in this review. RESULTS: A total of 54 articles were deemed eligible for review. Results from the quantitative literature revealed that parents of children with food allergy (ie, food allergy and food protein-induced enterocolitis, proctocolitis, and enteropathy) consistently reported lower quality of life than their comparison groups. Within-group analyses suggest that this burden is increased for parents who manage multiple food allergies, severe food allergy, and comorbid allergic conditions. Thematic synthesis of the qualitative literature suggests that the psychosocial burden shouldered by parents of children with food allergy stems, in part, from the unpredictable threat of exposure and the practical and social burdens of managing a food allergy. In addition to psychosocial burdens, a small but growing body of literature suggests that families with food allergy also incur greater financial costs. CONCLUSION: Findings suggest that pediatric food allergy imposes considerable burdens on parents both quantitatively and qualitatively.

Distinguishing benign from pathologic TH2 immunity in atopic children.

BACKGROUND: Although most children with asthma and rhinitis are sensitized to aeroallergens, only a minority of sensitized children are symptomatic, implying the underlying operation of efficient anti-inflammatory control mechanisms. OBJECTIVE: We sought to identify endogenous control mechanisms that attenuate expression of IgE-associated responsiveness to aeroallergens in sensitized children. METHODS: In 3 independent population samples we analyzed relationships between aeroallergen-specific IgE and corresponding allergen-specific IgG (sIgG) and associated immunophenotypes in atopic children and susceptibility to asthma and rhinitis, focusing on responses to house dust mite and grass. RESULTS: Among mite-sensitized children across all populations and at different ages, house dust mite-specific IgG/IgE ratios (but not IgG4/IgE ratios) were significantly lower in children with asthma compared with ratios in those without asthma and lowest among the most severely symptomatic. This finding was mirrored by relationships between rhinitis and antibody responses to grass. Depending on age/allergen specificity, 20% to 40% of children with allergen-specific IgE (sIgE) of 0.35 kU/L or greater had negative skin test responses, and these children also expressed the high sIgG/sIgE immunophenotype. sIgG1 from these children inhibited allergen-induced IgE-dependent basophil activation in a dose-dependent fashion. Profiling of aeroallergen-specific CD4(+) TH memory responses revealed positive associations between sIgG/sIgE ratios and IL-10-dependent gene signatures and significantly higher IL-10/TH2 cytokine (protein) ratios among nonsymptomatic children. CONCLUSION: In addition to its role in blocking TH2 effector activation in the late-phase allergic response, IL-10 is a known IgG1 switch factor. We posit that its production during allergen-induced memory responses contributes significantly to attenuation of inflammation through promoting IgG1-mediated damping of the FcεRI-dependent acute-phase reaction. sIgG1/sIgE balance might represent a readily accessible therapeutic target for asthma/rhinitis control.

Innate IgG molecules and innate B cells expressed by immunoglobulin constant heavy G chain (Fcγ) genetic marker genes are involved in the 'allergic march' of IgE sensitization in children.

BACKGROUND: Interindividual variations of immunoglobulin constant heavy G chain (IGHG) genes on chromosome 14q32.3 are identified by alternative genetic markers (GM) of IgG3, IgG1 and IgG2, respectively. They express structurally and functionally innate IgG molecules and B cells, associated with allergic disease, replicated in several studies. MATERIALS AND METHODS: 1-year-old and 10-year-old, IgE-sensitized and non-sensitized children from the German Multicenter Allergy Study birth cohort were assessed by new serological methods for the mendelian IGHG (Fcγ) (GM) genes, as innate IgG molecules and innate B cells. RESULTS: Food allergy sensitization in thirty-five 1-year-old children (124 not sensitized) was associated with the IGHG*bfn haplotype and B*(bfn) cells (OR 1.9, 95% CI 1.2-3.1; p = 0.010). Aeroallergen sensitization in ninety-nine 10-year-old children (95 not sensitized) was associated with the same genes (OR 1.4, 95% CI 1.02-1.9; p = 0.034). The IgE sensitization was most prominent in the restrictive homozygous IGHG*bfn/*bfn diplotype, 34% at age 1, increasing to 60% at age 10, rating the highest numbers of positive IgE tests, expressing increased levels of IgE and innate IgG2*n. CONCLUSIONS: The IGHG*bfn haplotype (B*(bfn) cells) and increased innate IgG2*n levels are predictive factors for IgE sensitization in childhood. IGHG genes can be assessed for prognostic and preventive purposes in clinical care.

Allergen-specific IgG antibody levels modify the relationship between allergen-specific IgE and wheezing in childhood.

BACKGROUND: An increase in IgE antibody levels to inhalant allergens is associated with an increased likelihood of wheezing. The role of allergen-specific IgG and IgG4 in relation to wheezing is yet to be determined. OBJECTIVE: We sought to investigate whether Fel d 1-specific IgG and IgG4 antibodies modify the association between cat allergen-specific IgE and childhood wheezing. METHODS: We used data from 2 population-based birth cohorts (United Kingdom [UK], n = 473; Australia, n = 1336). Current wheeze was defined as wheezing in the previous 12 months at age 5 (UK) and 14 (Australia) years. We determined cat allergen-specific IgE (whole extract) and IgG and IgG4 antibody (purified rFel d 1) levels and used logistic regression to estimate the relationship between wheeze and the quantitative allergen antibody levels. RESULTS: In the univariate analysis risk of wheezing increased significantly with increasing cat-specific IgE levels (UK: odds ratio [OR], 1.56; 95% CI, 1.28-1.90; Australia: OR, 1.29; 95% CI, 1.19-1.40). rFel d 1-specific IgG or IgG4 had no significant effect on wheeze in either population. However, a different pattern of the relationship between antibody levels and wheezing emerged in the multivariate analysis. In the UK cat-specific IgE increased the risk of wheeze (OR, 2.01; 95% CI, 1.29-3.12; P = .002), whereas rFel d 1-specific IgG decreased the risk (OR, 0.46; 95% CI, 0.21-0.99; P = .05). This finding was replicated in Australia (IgE: OR, 1.46; 95% CI, 1.28-1.68; P < .001; IgG: OR, 0.66; 95% CI, 0.44-0.99; P = .049). There was no significant association between IgG4 antibody levels and wheezing in either population. CONCLUSIONS: rFel d 1-specific IgG but not IgG4 antibody levels significantly modify the association between cat-specific IgE and childhood wheezing, with the risk of symptoms decreasing with increasing IgG levels.

Peanut allergy: Clinical and immunologic differences among patients from 3 different geographic regions.

BACKGROUND: Peanut allergy affects persons from various geographic regions where populations are exposed to different dietary habits and environmental pollens. OBJECTIVE: We sought to describe the clinical and immunologic characteristics of patients with peanut allergy from 3 countries (Spain, the United States, and Sweden) using a molecular component diagnostic approach. METHODS: Patients with peanut allergy from Madrid (Spain, n = 50), New York (United States, n = 30), Gothenburg, and Stockholm (both Sweden, n = 35) were enrolled. Clinical data were obtained either from a specific questionnaire or gathered from chart reviews. IgE antibodies to peanut extract and the peanut allergens rAra h 1, 2, 3, 8 and 9, as well as to cross-reactive birch (rBet v 1) and grass (rPhl p 1, 5, 7, and 12) pollen allergens, were analyzed. RESULTS: American patients frequently had IgE antibodies to rAra h 1 to 3 (56.7% to 90.0%) and often presented with severe symptoms. Spanish patients recognized these 3 recombinant peanut allergens less frequently (16.0% to 42.0%), were more often sensitized to the lipid transfer protein rAra h 9 (60.0%), and typically had peanut allergy after becoming allergic to other plant-derived foods. Swedish patients detected rAra h 1 to 3 more frequently than Spanish patients (37.1% to 74.3%) and had the highest sensitization rate to the Bet v 1 homologue rAra h 8 (65.7%), as well as to rBet v 1 (82.9%). Spanish and Swedish patients became allergic to peanut at 2 years or later, whereas the American children became allergic around 1 year of age. CONCLUSIONS: Peanut allergy has different clinical and immunologic patterns in different areas of the world. Allergen component diagnostics might help us to better understand this complex entity.

The Economic Burden of Food Allergy: What We Know and What We Need to Learn.

Purpose of Review: Food allergy management and treatment require dietary modification, are associated with significant burdens, and affect food choices and behaviours. Emerging therapies, such as oral immunotherapy (OIT), provide a glimmer of hope for those living with the condition. Some burdens have received substantial focus, whereas many knowledge gaps on the significance of other impacts, including economic burden, remain. Recent Findings: Evidence from many countries, but disproportionately from the United States, supports that food allergy carries significant healthcare and societal costs. Early introduction for the prevention of food allergies is theoretically cost-effective, but remains largely undescribed. Unique considerations, such as those to cow's milk protein allergy, which affects a substantial proportion of infants, and adrenaline autoinjectors, which have a high cost-per-use, require a balance between cost-effectiveness to the healthcare system and adverse outcomes. Household costs have largely been explored in two countries, but owing to different healthcare structures and costs of living, comparisons are difficult, as are generalisations to other countries. Stock epinephrine in schools may present a cost-effective strategy, particularly in economically disadvantaged areas. Costs relating to OIT must be examined within both immediate benefits, such as protection from anaphylaxis, and long-term benefits, such as sustained unresponsiveness. Summary: Although the absolute costs differ by region/country and type of food allergy, a consistent pattern persists: food allergy is a costly condition, to those who live with it, and the multiple stakeholders with which they interact. Supplementary Information: The online version contains supplementary material available at 10.1007/s40521-022-00306-5.

Evaluation of IgE antibodies to recombinant peanut allergens in patients with reported reactions to peanut.

BACKGROUND: Peanut may cause severe reactions in allergic individuals. The objective was to evaluate IgE antibodies to various recombinant (r) peanut and birch pollen allergens in relation to IgE levels to whole peanut extract and severe allergic reactions to peanut. METHODS: Seventy-four Swedish peanut-allergic patients (age: 14-61 years) reported previous peanut exposure and associated symptoms using a questionnaire. Their IgE reactivity to peanut, birch pollen and individual allergen components was analyzed using ImmunoCAP. RESULTS: Of the 48 subjects sensitized to Ara h 1, 2 or 3, 60% had peanut-specific IgE levels >15 kU(A)/l, while 100% of the subjects without detectable IgE to these allergens had low peanut-specific IgE levels (<10 kU(A)/l). The levels of IgE to rAra h 8, rBet v 1 and birch pollen were highly correlated (r(S) = 0.94, p < 0.0001). Fifty-eight patients reported adverse reactions after accidental or deliberate peanut exposure (oral, inhalation or skin) of whom 41 had IgE to rAra h 1, 2 or 3. Symptoms of respiratory distress were associated with sensitization to Ara h 1, 2 or 3 (56 vs. 18%, p < 0.01). Two cases of anaphylaxis were reported among the individuals sensitized to Ara h 1-3. IgE to rAra h 8, rAra h 9, profilin or cross-reactive carbohydrate determinants were not associated with severe symptoms. CONCLUSIONS: The results indicate that IgE reactivity to Ara h 1, 2 and 3 is associated with severe reactions after exposure to peanut in Swedish patients.

Allergy or tolerance in children sensitized to peanut: prevalence and differentiation using component-resolved diagnostics.

BACKGROUND: Not all peanut-sensitized children develop allergic reactions on exposure. OBJECTIVE: To establish by oral food challenge the proportion of children with clinical peanut allergy among those considered peanut-sensitized by using skin prick tests and/or IgE measurement, and to investigate whether component-resolved diagnostics using microarray could differentiate peanut allergy from tolerance. METHODS: Within a population-based birth cohort, we ascertained peanut sensitization by skin tests and IgE measurement at age 8 years. Among sensitized children, we determined peanut allergy versus tolerance by oral food challenges. We used open challenge among children consuming peanuts (n = 45); others underwent double-blind placebo-controlled challenge (n = 34). We compared sensitization profiles between children with peanut allergy and peanut-tolerant children by using a microarray with 12 pure components (major peanut and potentially cross-reactive components, including grass allergens). RESULTS: Of 933 children, 110 (11.8%) were peanut-sensitized. Nineteen were not challenged (17 no consent). Twelve with a convincing history of reactions on exposure, IgE > or =15 kUa/L and/or skin test > or =8mm were considered allergic without challenge. Of the remaining 79 children who underwent challenge, 7 had > or =2 objective signs and were designated as having peanut allergy. We estimated the prevalence of clinical peanut allergy among sensitized subjects as 22.4% (95% CI, 14.8% to 32.3%). By using component-resolved diagnostics, we detected marked differences in the pattern of component recognition between children with peanut allergy (n = 29; group enriched with 12 children with allergy) and peanut-tolerant children (n = 52). The peanut component Ara h 2 was the most important predictor of clinical allergy. CONCLUSION: The majority of children considered peanut-sensitized on the basis of standard tests do not have peanut allergy. Component-resolved diagnostics may facilitate the diagnosis of peanut allergy.

Toward improved prediction of risk for atopy and asthma among preschoolers: a prospective cohort study.

BACKGROUND: Atopy and asthma are commonly initiated during early life, and there is increasing interest in the development of preventive treatments for at-risk children. However, effective methods for assessing the level of risk in individual children are lacking. OBJECTIVE: We sought to identify clinical and laboratory biomarkers in 2-year-olds that are predictive of the risk for persistent atopy and wheeze at age 5 years. METHODS: We prospectively studied 198 atopic family history-positive children to age 5 years. Clinical and laboratory assessments related to asthma history and atopy status were undertaken annually; episodes of acute respiratory illness were assessed and classified throughout and graded by severity. RESULTS: Aeroallergen-specific IgE titers cycled continuously within the low range in nonatopic subjects. Atopic subjects displayed similar cycling in infancy but eventually locked into a stable pattern of upwardly trending antibody production and T(H)2-polarized cellular immunity. The latter was associated with stable expression of IL-4 receptor in allergen-specific T(H)2 memory responses, which was absent from responses during infancy. Risk for persistent wheeze was strongly linked to early sensitization and in turn to early infection. Integration of these data by means of logistic regression revealed that attaining mite-specific IgE titers of greater than 0.20 kU/L by age 2 years was associated with a 12.7% risk of persistent wheeze, increasing progressively to an 87.2% risk with increasing numbers of severe lower respiratory tract illnesses experienced. CONCLUSION: The risk for development of persistent wheeze in children can be quantified by means of integration of measures related to early sensitization and early infections. Follow-up studies along similar lines in larger unselected populations to refine this approach are warranted.

The use of serum-specific IgE measurements for the diagnosis of peanut, tree nut, and seed allergy.

BACKGROUND: The gold standard for diagnosing food allergy is the double-blind, placebo-controlled food challenge. Diagnostic food-specific IgE levels might assist in diagnosing food allergies and circumventing the need for food challenges. OBJECTIVES: The purpose of this study was to determine the utility of food-specific IgE measurements for identifying symptomatic peanut, tree nut, and seed allergies and to augment what is known about the relationships among these foods. METHODS: Patients referred for suspected peanut or tree nut allergies answered a questionnaire about their perceived food allergies. Allergen-specific diagnoses were based on questionnaire, medical history, and, when relevant, skin prick tests and serum specific IgE levels. Sera from the patients were analyzed for specific IgE antibodies to peanuts, tree nuts, and seeds by using ImmunoCAP Specific IgE (Phadia, Inc, Uppsala, Sweden). RESULTS: Three hundred twenty-four patients (61% male; median age, 6.1 years; range, 0.2-40.2 years) were evaluated. The patients were highly atopic (57% with atopic dermatitis and 58% with asthma). The majority of patients with peanut allergy were sensitized to tree nuts (86%), and 34% had documented clinical allergy. The relationship between diagnosis and allergen-specific IgE levels were estimated by using logistic regression. Diagnostic decision points are suggested for peanut and walnut. Probability curves were drawn for peanut, sesame, and several tree nuts. High correlations were found between cashew and pistachio and between pecan and walnut. CONCLUSIONS: Quantification of food-specific IgE is a valuable tool that will aid in the diagnosis of symptomatic food allergy and might decrease the need for double-blind, placebo-controlled food challenges.

Food allergy-related concerns during the transition to self-management.

BACKGROUND: Compared to non-allergic individuals, food allergic individuals have impaired health-related quality of life (HRQL). However, effects of gender and age are unclear. The objective of our study was to describe associations between allergies to common foods and HRQL with consideration to gender and age. METHODS: Adolescents and adults (N = 137; 49.6% males) with specialist-diagnosed allergy to milk, egg and/or wheat completed age-appropriate versions of the Food Allergy Quality of Life Questionnaire (FAQLQ). We pooled common questions and calculated overall- and domain-specific HRQL in association with number and severity of symptoms and time elapse since worst reaction. RESULTS: In the entire study population, HRQL was not affected by gender or age, whereas gender-specific age categories affected HRQL among males only. For example, males 18-39 years had worse overall- (ß = 0.77; 95% CI 0.08-1.45) and domain-specific HRQL vs. males < 18 years. Among participants with 1-3 food allergy symptoms, no associations were found. Among participants with 4-6 symptoms, the domain allergen avoidance and dietary restrictions was worse among older participants (e.g. 40+ years: ß = 0.71; 95% CI 0.05-1.37 vs. < 18 years), and males 18-39 vs. < 18 years. Among participants with severe symptoms, females vs. males, and participants 18-39 vs. < 18 years had worse HRQL. At least 4 years since worst reaction was associated with worse HRQL for participants 40+ years vs. < 18 years, and older males vs. males < 18 years. Nearly all differences exceeded the clinical relevance threshold of ≥ 0.5. CONCLUSIONS: Associations between allergies to common foods and HRQL are affected by gender and age. Most affected are males 18-39 years. Among females, HRQL is more stable across age groups.

Pediatric food allergy-related household costs are influenced by age, but not disease severity.

OBJECTIVE: The economic burden of food allergy on households is poorly understood. We evaluated the household costs associated with specialist-diagnosed pediatric food allergy, with focus on age and disease severity. STUDY DESIGN: A cross-sectional study of 70 Swedish case-control pairs (59% boys) was conducted using Food Allergy Economic questionnaire. Household costs were analyzed between age- and gender-matched cases (children aged 0-17 years, with specialist-diagnosed food allergy) and controls (non-food allergic households). RESULTS: Parents were predominantly university-educated and employed full-time. Most cases had parent-reported previous anaphylaxis. Mean total annual household costs were comparable between cases and controls. However, compared to controls, cases had significantly higher direct medical-, and non-medical related costs; higher indirect medical-related costs, and higher intangible costs (all p < 0.05). In a sensitivity analyses of only cases aged 0-12 years, direct household costs, including lost earnings due to child's hospitalization, were significantly higher than controls. Results from only children with severe disease paralleled those of all cases vs. controls. CONCLUSIONS: Although pediatric food allergy is not associated with higher total annual household costs, these households have significantly higher direct medical-related, indirect and intangible costs vs. non-food allergic households. Higher household costs were identified amongst younger children, but not disease severity.

Health-related quality of life worsens by school age amongst children with food allergy.

BACKGROUND: Food allergy is negatively associated with health-related quality of life (HRQL). Although differences exist between parents and children, less is known about age-specific differences amongst children. As such, we aimed to identify if age, as well as other factors, are associated with food allergy-specific HRQL in an objectively defined population of children. METHODS: Overall, 63 children (boys: n = 36; 57.1%) with specialist-diagnosed food allergy to 1 + foods were included. Parents/guardians completed the Swedish version of a disease-specific questionnaire designed to assess overall- and domain-specific HRQL. Descriptive statistics and linear regression were used. RESULTS: The most common food allergy was hen's egg (n = 40/63; 63.5%). Most children had more than one food allergy (n = 48; 76.2%). Nearly all had experienced mild symptoms (e.g. skin; n = 56/63; 94.9%), and more than half had severe symptoms (e.g. respiratory; 39/63; 66.1%). Compared to young children (0-5 years), older children (6-12 years) had worse HRQL (e.g. overall HRQL: B = 0.60; 95% CI 0.05-1.16; p < 0.04.). Similarly, multiple food allergies, and severe symptoms were significantly associated with worse HRQL (all p < 0.05) even in models adjusted for concomitant allergic disease. No associations were found for gender or socioeconomic status. CONCLUSION: Older children and those with severe food allergy have worse HRQL.

Food hypersensitivity and quality of life.

PURPOSE OF REVIEW: The present article presents an accessible review of research results on food hypersensitivity and quality of life (QoL), including 15 original articles on the subject. RECENT FINDINGS: Research on food hypersensitivity and QoL covers children and their parents, adolescents and adults. Several domains of QoL are affected, such as family and social activities, emotional issues and family economy. Food-hypersensitive children are to a large extent limited in their autonomous social activities. Food-allergic adolescents have a higher number of weeks absent from school compared with a control group, and a relatively high percentage of food-allergic young adults do not participate in the labour market. Comorbidity has to be taken into consideration when assessing QoL in food-hypersensitive individuals. Research on gender differences in food hypersensitivity and QoL are scarce. SUMMARY: Although development in this research field has only just begun, it is obvious that food hypersensitivity has a significant impact on individuals' and families' QoL. An important advance is the disease-specific QoL measure instruments that have been created. There is still, however, a need for a more in-depth knowledge as a basis for further development of QoL instruments, and as a basis for societal interventions and family/individual support.

Adolescents' experiences of being food-hypersensitive: a qualitative study.

BACKGROUND: Experiencing or being at risk of adverse reactions to certain food items is a common health issue, especially among children and adolescents. Research has shown that living with the risk of food reactions and always having to take measures to avoid certain food in one's diet has a negative impact on quality of life. The aim of this study was to illuminate adolescents' experiences of being food hypersensitive. METHODS: Three focus group interviews and six individual interviews were carried out with all together 17 adolescents, 14-18 years of age, who had exclusion diets at school due to food hypersensitivity. The interviews were taped and transcribed verbatim and a qualitative content analysis was carried out. RESULTS: Five categories with subcategories, and one pervading theme, emerged. The categories were: Perceiving oneself as being particular, Feeling constrained, Experiencing others' ignorance, Keeping control, and Feeling it's okay. A pervading theme was conceptualised as Striving to normalise the experience of being food-hypersensitive. The adolescents regarded themselves as competent and courageous, but also described how they avoided the extra attention it implied to ask for special food considerations taken into account. Their self-conceptions were probably essential for their management of and attitude toward the hypersensitivity condition. They felt deprived, and those at risk of severe food reactions experienced insecurity and fear. Feelings of being disregarded were expressed, as well as facing unreliability and a lack of understanding from others. The continual work of constant vigilance and decision-making was described as time-consuming and frustrating. However, the adolescents also experienced considerate and supportive surroundings and were at pains to tone down the negative experiences and consequences of being food-hypersensitive. CONCLUSION: Food avoidance by itself, and not only the somatic food reactions, brings about consequences with significant impacts on adolescents' lives. The findings from this study have implications for all of those who deal with adolescents who are food-hypersensitive, and not only health professionals. A deeper insight into adolescents' experiences gives an understanding which can improve the care-givers' efforts.