The role of agricultural biodiversity, dietary diversity, and household food security in households with and without children with stunted growth in rural Kenya

M'Kaibi, Florence K. (2014-04)

Thesis (PhD)--Stellenbosch University, 2014.

Thesis

ENGLISH ABSTRACT: Research aim The study aimed to explore the associations between agricultural biodiversity, household food security and dietary diversity in households with children aged 24 to 59 months in two rural areas of Kenya, of which one had higher rainfall and agricultural biodiversity than the other. Methods Study sample and location The study adopted a cross-sectional analytical approach to investigate the associations in resource in poor households in two rural areas; Akithii and Uringu of Kenya. Of the 525 households randomly selected, 261 were from Uringu division and 264 from Akithii division. Two independent cross-sectional surveys were conducted; Phase one in September to October 2011 (during the dry season) while Phase 2 took place in March 2012 (during the rainy season). A questionnaire was developed to gather information on the socio-demographics of the household, breastfeeding and infant feeding practices, immunization and childhood illnesses. Dietary intake was measured during each season by conducting a repeated 24-hour recall (24-hr recall) with the mother/care giver of the household. A nutrient adequacy ratio (NAR) was calculated for each nutrient as the percent of the nutrient meeting the recommended dietary intake (RDI) value for that nutrient. A mean adequacy ratio (MAR) was calculated for 11 nutrients as the mean of the NARs of these nutrients. Dietary diversity was measured using data from the 24-hour recalls and classifying it into nine food groups. A dietary diversity score (DDS) was calculated based on each different food group which was consumed during the period of recall up to a maximum of nine if the food had been consumed from each of the nine groups. Household food security (HFS) was measured using the Household Food Insecurity Access Scale (HFIAS). The agricultural biodiversity was calculated by counting the number of different crops and animals eaten either from domestic sources or from the wild. Weight and height measurements of children and their mothers/care givers were taken. Weight for age (WAZ), height for age (HAZ) and weight for height z (WHZ) scores were determined for children, while body mass index (BMI) measurements were calculated for the adult women. The relationships between continuous response variables and nominal input variables were analyzed using appropriate analysis of variance (ANOVA) or pooled, paired and independent mean T-tests when only two groups were involved. Results Dietary intake was low with the majority of households not meeting the RDIs for most nutrients. The MAR was 61.3%; 61.8% for Phase 1 and 2 respectively. The DDS was low at 3.3 ±1.2 for both Phases. The majority of households were food insecure with a HFIAS mean of 12.8 ± 6.19 and 10.9 ± 7.49 for Phase 1 and 2 respectively. Agricultural biodiversity was low with a total of 26 items; 23 domesticated and 3 from the natural habitat. Two food items from the natural habitat originated from plants and one from animals. Exclusive breastfeeding up to the recommended six months was practiced at low rates of 23.4% while 39.3% of mothers in both divisions introduced complementary foods before 6 months of age. Stunted growth among the children was high at a mean of 30.5% (n=291). Boys had higher stunted growth rates in both divisions compared to the girls. A significant positive relationship was established between the number of contributors to household income with height for age z-scores (HAZ) scores of the children (Spearman r=-0.15, p=0.02). The number of household assets also significantly influenced HAZ scores (Spearman r=-0.17, p=0.01), the higher the number of household assets, the lower HAZ scores were. During Phase 1 (dry season) (pooled t-test, p<0.001), levels of food insecurity were higher compared to Phase 2 (wet season) (pooled t-test, p<0.001); showing the influence of season on food security. Phases 1 & 2 showed that Akithii had a significantly higher level of food insecurity (Mann-Whitney U; p<0.01), and a lower DDS (chi-square test, p<0.001) compared to Uringu. Children in Akithii consumed a less diversified diet than those in Uringu. Agricultural biodiversity was positively and significantly related to: HFIAS (Spearman r=-0.10, p=0.02); DDS (ANOVA, p<0.001); all NARs (Spearman, p<0.05) and MAR (Spearman, p<0.001).This implies that households with higher agricultural biodiversity were more likely to be food secure, have higher dietary diversity levels and a diet comprising a higher nutritional value. DDS was significantly correlated to MAR and NARs of all the nutrients studied in this study. Findings showed that DDS was also consistently significantly inversely correlated to Household Food Insecurity Access Prevalence (HFIAP) (R =-0.185, t (N-2)-3.889), p=0.0001). This correlation showed that an increase in dietary diversity inversely affected HFIAS. A significant relationship was found between HFIAP and MAR (ANOVA, p=0.00268); indicating that households with a higher MAR were more likely to be food secure. There was a significant correlation between the BMI of the mother/care giver and the WAZ scores of the children (r=0.1410, p<0.001); indicating that higher HAZ scores were found in mothers with higher mean BMI values. There was a significant difference between households with and without children with stunted growth in DDS (ANOVA; p=0.047) and HFIAS (ANOVA; p=0.009) but not with agricultural biodiversity score (ANOVA; p=0.486). The agricultural biodiversity mean score for households with children presenting with stunted growth were, however, lower at 6.8, compared to 7.0 for those with normal growth however the p value was not significant. This indicates that households with children with stunted growth and those without are significantly different in DDS and HFIAS but not regarding agricultural biodiversity. This further implies that the potential of DDS and HFIAS to be used as proxy measures for stunting be further explored. Conclusion Agricultural biodiversity has a positive impact on household food security, dietary diversity, dietary adequacy and child growth. Food security is closely linked to dietary diversity and dietary adequacy; therefore improving one is likely to improve the other two and impact positively on child growth status. Interventions to improve child health and food security in resource poor rural households should aim at increasing dietary diversity through agricultural biodiversity.

AFRIKAANSE OPSOMMING: Navorsingsdoel Die studie is daarop gemik om die assosiasies tussen die landbou-biodiversiteit, huishoudelike voedselsekerheid en dieetdiversiteit in huishoudings met kinders tussen die ouderdomme van 24 tot 59 maande in twee landelike gebiede van Kenia, waarvan een 'n hoër reënval en landbou-biodiversiteit as die ander gehad het, te verken. Metodes Studie steekproef en plek Die studie het 'n deursnit-analitiese benadering aangeneem om die assosiasies te ondersoek in hulpbron-arm huishoudings in twee landelike gebiede; Akithii en Uringu van Kenia. Van die 525 huishoudings wat ewekansig gekies is, was 261 van Uringu afdeling en 264 van Akithii afdeling. Twee onafhanklike deursnit-opnames is uitgevoer; fase een in September tot Oktober 2011 (tydens die droë seisoen), terwyl Fase 2 in Maart 2012 (gedurende die reënseisoen) plaasgevind het. 'n Vraelys is ontwikkel om inligting oor die sosio-demografie van die huishouding, borsvoeding en babavoeding praktyke, immunisering en kindersiektes in te samel. Dieetinname is gemeet tydens elke seisoen deur die uitvoer van 'n herhaalde 24-uur herroep met die moeder / versorger van die huishouding. 'n Voedingstof toereikendheidsverhouding (VTR) is bereken vir elke voedingstof, uitgedruk as die persentasie van die voedingstof wat voldoen aan die aanbevole dieetinname (ADI) waarde vir daardie voedingstof. 'n Gemiddelde toereikendheidsverhouding (GTR) is bereken vir 11 voedingstowwe uitgedruk as die gemiddelde van die VTR‘s van hierdie voedingstowwe. Dieetdiversiteit is gemeet deur data vanuit die 24-uur herroepe, geklassifiseer in nege voedselgroepe. 'n Dieetdiversiteit telling (DDT) is bereken op grond van elke verskillende voedselgroep wat gedurende die tydperk van herroep ingeneem is tot 'n maksimum van nege, indien die voedsel verbruik is uit elk van die nege groepe. Huishoudelike voedselsekerheid (HVS) is gemeet deur die huishoudelike voedselonsekerheid toegangskaal (HVOTS) te gebruik. Die landbou-biodiversiteit is bereken deur die som te bereken van die aantal verskillende gewasse en diere geëet óf van huishoudelike bronne óf uit die natuur. Gewig en lengte metings is geneem van die kinders en hul moeders / versorgers. Gewig vir ouderdom (GVO), lengte vir ouderdom (LVO) en gewig vir lengte (GVL) Z-tellings is bepaal vir die kinders, terwyl die liggaamsmassa-indeks (LMI) metings bereken is vir die volwasse vroue. Die verhoudings tussen aaneenlopende reaksie veranderlikes en nominale inset veranderlikes is ontleed met behulp van toepaslike analise van variansie (ANOVA) of saamgevoegde, gepaarde en onafhanklike gemiddelde T-toetse, indien slegs twee groepe betrokke was. Resultate Dieetinname was laag en die meerderheid van huishoudings het nie aan die ADIs vir die meeste voedingstowwe voldoen nie. Die GTR is 61,3% en 61,8% vir onderskeidelik fase 1 en 2. Die DDT is laag; 3,3 ±1,2 vir beide fases. Die meerderheid van huishoudings was voedselonseker met 'n gemiddelde HVOST van 12,8 ±6,19 en 10,9 ±7,49 vir onderskeidelik fase 1 en 2. Landbou-biodiversiteit was laag met 'n totaal van 26 items, 23 huishoudelike en 3 vanuit die natuurlike habitat. Twee voedselitems uit die natuurlike habitat was afkomstig van plante en een vanaf diere. Eksklusiewe borsvoeding, tot die aanbevole ses maande, was laag en beoefen deur 23,4%, terwyl 39,3% van die moeders, in beide streke, komplimentêre voedsel voor 6 maande ouderdom bekendgestel het. Vertraagde groei onder die kinders was hoog met 'n gemiddeld van 30,5% (n=291). Seuns het hoër vertraagde groei in beide streke in vergelyking met dogters getoon. ʼn Beduidende positiewe verhouding is gevind tussen die aantal bydraers tot huishoudelike inkomste en lengte vir ouderdom z-tellings (LOZ) van die kinders (Spearman r=-0,15, P=0,02). Die aantal huishoudelike bates het ook LOZ tellings (Spearman r=-0,17, P=0,01) aansienlik beïnvloed; hoe hoër die aantal huishoudelike bates, hoe laer die LOZ tellings. Tydens fase 1 (droë seisoen) (saamgevoegde t-toets, p<0.001), was vlakke van voedselonsekerheid hoër in vergelyking met fase 2 (nat seisoen) (saamgevoegde t-toets, p <0.001), wat die invloed van die seisoenaliteit op voedeselsekerheid uitwys. Fase 1 en 2 het gewys dat Akithii ʼn beduidende hoër vlak van voedselonsekerheid gehad het (Mann-Whitney U; p<0.01) en ʼn laer DDT (chi-square toets, p<0.001) in vergelyking met Uringu. Kinders in Akithii het ʼn dieet laer in diversiteit ingeneem as die in Uringu. Landbou-biodiversiteit is positief en beduidend verwant aan: HVOTS (Spearman r = -0,10, P = 0,02); DDT (ANOVA, p<0.001), alle VTR‘s (Spearman, p <0.05) en GTR (Spearman, p <0.001). Dit impliseer dat huishoudings met 'n hoër landbou-biodiversiteit, meer geneig is om voedselseker te wees, hoër dieetdiversiteit vlakke en ʼn hoër voedingswaarde het. DDT is beduidend gekorreleer aan GTR en VTT‘s van al die voedingstowwe wat bestudeer is in hierdie studie. Bevindinge het getoon dat DDT konsekwent en beduidend omgekeerd gekorreleer is met huishoudelike voedselonsekerheid toegang prevalensie (HVOTP) (R=-0,185, t(N-2)-3,889), p=0,0001). Hierdie korrelasie toon dat 'n toename in dieetdiversiteit HVOTS omgekeerd beïnvloed het. ʼn Betekenisvolle verhouding is gevind tussen HVOTP en GTR (ANOVA, p=0,00268); wat aandui dat huishoudings met 'n hoër GTR meer geneig is om voedselsekerheid te toon. Daar is 'n beduidende korrelasie tussen die LMI van die moeder / versorger en die GOZ tellings van die kinders (r=0,1410, p<0.001), wat aandui dat hoër LOZ tellings gevind is in moeders met hoër gemiddelde LMI waardes. Daar is 'n beduidende verskil tussen huishoudings met en sonder kinders met dwerggroei se DDT (ANOVA; p=0.047) en HVOTS (ANOVA; p=0.009) maar nie die landbou-diversiteit telling nie (ANOVA; p=0.486). Die gemiddelde landbou-diversiteit telling vir huishoudings met en sonder kinders met dwerggroei is egter laer met 6.8 in vergelyking met 7.0 vir die met normale groei. Die p-waarde is egter nie beduidend nie. Dit dui aan dat huishoudings met kinders met dwerggroei en daarsonder beduidend verskillend is ten opsigte van DDT en HVOTS, maar nie met landbou-diversiteit in die studie nie. Dit impliseer verder dat die potensiaal van DDT en HVOTS om gebruik te word as alternatiewe metings vir dwerggroei verder ondersoek moet word. Gevolgtrekking Landbou-biodiversiteit het 'n positiewe impak op huishoudelike voedselsekerheid, dieetdiversiteit, dieettoereikendheid en groei van kinders. Voedselsekerheid is nou gekoppel aan dieetdiversiteit en dieettoereikendheid, daarom sal die verbetering van die een waarskynlik die ander twee positief beïnvloed asook ʼn positiewe impak hê op die groei van kinders. Intervensies vir die verbetering van kindergesondheid en voedselsekerheid in hulpbron-arm landelike huishoudings moet poog om dieetdiversiteit te verhoog deur landbou-biodiversiteit.

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