Comparison of the dietary intake of the urban black population in Cape Town in 1990 with 2009

Jaffer, Nasreen (2017-03)

Thesis (MNutr)--Stellenbosch University, 2017.

Thesis

ENGLISH SUMMARY : Background: In 1990 the BRISK was undertaken in the black population in five townships in Cape Town, Langa, Gugulethu, Khayalitsha, Nyanga, and Crossroads. The prevalence of noncommunicable diseases (diabetes and heart disease) and their risk factors, including dietary intake were investigated. Aim: To determine the dietary intake of the urban black population (25–64 years) of Cape Town in 2009 and compare these findings with a similar sample examined in the same townships in 1990. Study design and sample: A cross-sectional survey including a representative sample of 392 males and 707 females (n=1099) was drawn from the same townships as in 1990. Methods: Socio-demographic data were collected by trained field workers. Weight, height, and waist and hip circumference were measured. Body mass index (BMI), and waist- hip ratio (WHR) were calculated. Dietary intake data (macro- and micronutrients, mean adequacy ratio (MAR), food groups and portion sizes) were calculated using the MRC FoodFinder program and compared with the dietary reference intakes. The MAR was calculated for each participant. Data analyses: Anthropometric and dietary data are presented as means and standard deviations by age, level education, type of housing, degree of urbanisation and asset index (proxy for socioeconomic status). Associations of dietary data with anthropometric and biochemistry data (TC, HDLC, LDL-C, and glucose), blood pressure, asset index, and degree of urbanisation were assessed. A linear regression model was computed using MAR as the dependent variable and adding age, gender, urbanisation, asset index and other variables to the model. Correlations between the asset index and urbanisation duration were done with energy and nutrient intakes using Pearson’s correlations. Regressions were done to test the significance of various variables. Results: Most of the adults had an education of at least 8–12 years, though 60% of the males and 58.3% of females were unemployed, and 13.8% were pensioners. Twenty-one per cent lived in formal houses, 35.4% in council houses or hostels, and 43.6% in shacks. Only 12.1% of adults had spent less than 20% of their life in an urban area. Thirty three per cent were classified as falling within the poorest tertile of the asset index. The percentage of adults with a BMI greater than 30 kg/m2 was 63.3% in females and 12% in males. Males had a WC and WHR of 85.7 cm and 0.89 and females 97.5 cm and 0.85, respectively. Analysis of the 24-hour dietary recall data showed very low mean energy intakes [M 6516 (2929); F 5760 (2446) kJ]. These results did not support the high prevalence of obesity, particularly in females, and also in four other studies among urban black populations. Hence the Goldberg equation was used to remove under-reporters. The remaining sample comprised 544 (214 males and 330 females) participants residing in Khayelitsha (42.4%), Langa (31.4%), Gugulethu (15.3%), and less than 10% in Crossroads and Nyanga. After removal of the under-reporters, mean energy intakes were similar to those of the 1990 study and in 25–44-year-old males were 8557 kJ compared to 8500 kJ in 1990. In females they were 7619 kJ compared with 6400 kJ in 1990. Fat intakes were highest in 25–44-year-old males (32% energy [E]) and females (33.4% E) in 2009 compared to 1990 (males: 25.9% E, females: 27.0% E). Carbohydrate intakes were lower in 2009 (males 53.2% E, females: 55.5% E) than in 1990 (males: 61.3% E; females: 62% E), while sugar intake increased significantly (p <0.01) in females. There were significant positive correlations between urbanisation and total fat (p=0.016), saturated fat (p=0.001), monounsaturated fat (p=0.002) and fat as a %E intake (p=0.046). Urbanisation was inversely associated with intake of carbohydrate %E (p <0.001). Overall micronutrient intakes improved significantly compared to 1990 with the exception of calcium intake. This is thought to be due to the national fortification of maize and wheat flour. Of note is that energy and macronutrient intakes were all significant in a linear regression model using the MAR, as was duration of urbanisation. The higher fat and lower carbohydrate %E intakes in this population demonstrate a transition to a more urbanised diet over the two decades. Forward regression was done to identify the significant variables which were then entered into a linear regression model. In males, BMI was significantly associated with protein intake, while in females BMI was related to saturated fat, saturated fat %E, carbohydrate, and carbohydrate %E. In terms of the duration of urbanisation it can be noted that carbohydrate %E, total fat %E energy, calcium, animal protein and total cholesterol were significant in males. In females, protein %E, carbohydrate %E, fat %E were significantly associated with greater urbanisation. In the 2009 study, milk products, the meat group, legumes, SF and brick margarine in males and females were found to be statistically lower than those in the 1990 study. This was also found in the cereal group, but only for the males. Despite this, the 2009 study for the males and females, showed significantly higher intakes of eggs, vitamin C rich fruits and vegetables and PUFA sources compared to the 1990 group. This was also found in the cereal group for females. The percentage consumers for red meat, white meat, eggs, vegetables and fruit, and cereals increased from 1990 to 2009. For the dairy and fat groups, the percentage consumers decreased. Conclusion: The nutrient intakes demonstrate that while certain changes have taken place between 1990 and 2009, the dietary pattern regarding foods eaten remains poor. The diet has become more urbanised and atherogenic with regard to fat distribution and carbohydrate intake, while the consumption of certain food groups has remained low, such as the poor consumption of dairy products and low intake of fruit and vegetables. However, overall mean micronutrient intakes increased to above the dietary reference intakes with the exception of calcium intake. Recommendation: Interventions are urgently needed to combat the shift towards a continuing atherogenic diet and to improving the consumption of priority food groups, such as dairy products, and fruit and vegetables.

AFRIKAANSE OPSOMMING : Agtergrond: In 1990 is die BRISK-studie onder die swart bevolking in vyf Kaapstadse woongebiede, Langa, Gugulethu, Khayalitsha, Nyanga, en Crossroads onderneem. Die voorkoms van nieoordraagbare siektes (diabetes en hartsiekte) en hulle risikofaktore, insluitend dieetinname is ondersoek. Doel: Om die dieetinname van die stedelike swart bevolking (25–64 jaar) van Kaapstad in 2009 te bepaal en hierdie bevindings met ’n soortgelyke steekproef uit dieselfde woongebiede as in 1990 te vergelyk. Studieontwerp en steekproef: ’n Deursnee-opname wat ’n verteenwoordigende steekproef van 392 mans en 707 vroue (n=1099) insluit, is getrek vanuit dieselfde woongebiede as in 1990. Metode: Sosiodemografiese data is deur opgeleide veldwerkers ingesamel. Gewig, lengte, en middel- en heupomtrek is gemeet. Die liggaamsmassa indeks (LMI) en middel- en heupverhouding (MHV) is bereken. Dieetinname data (makro- en mikronutriënte, gemiddelde toereikendheidsverhouding, voedselgroepe en porsiegroottes) is bereken met behulp van die MRC FoodFinder-program en vergelyk met die dieetverwysingsinnames. Die gemiddelde toereikendheidsverhouding is vir elke deelnemer bereken. Data analises: Antropometrie en dieetdata word as gemiddeldes en standaardafwykings volgens ouderdom, onderwysvlak, soort behuising, mate van verstedeliking en bate indeks (volmag vir ekonomiese status) aangebied. Assosiasies van dieetdata met antropometrie en biochemiese data (TC, HDL-C, LDL-C, en glukose), bloeddruk, die bate indeks en mate van verstedeliking is getakseer. ’n Lineêre regressiemodel is bereken met behulp van die gemiddelde toereikendheidsverhouding as afhanklike veranderlike en byvoeging van ouderdom, geslag, verstedeliking, bate indeks en ander veranderlikes tot die model. Korrelasies tussen bate indeks en duur van verstedeliking met energie en nutriëntinnames is met behulp van Pearson se korrelasies gedoen. Regressies is gedoen om die betekenisvolheid van verskeie veranderlikes te toets. Resultate: Die meeste volwassenes het ten minste 8–12 jaar opvoeding gehad alhoewel 60% mans en 58.3% vroue werkloos was, met 13.8% pensionarisse. Een-en-twintig persent het in formele huise gewoon, 35.4% in munisipale huise of hostelle en 43.6% in opslaanhutte. Slegs 12.1% volwassenes het minder as 20% van hulle lewe in ’n stedelike gebied spandeer. Ses-en-dertig is onder die armste tertiel van die bate indeks geklassifiseer. Die persentasie volwassenes met ’n LMI groter as 30 kg/m2 was 63.3% vir vroue en 12% vir mans. Mans het ’n middelomtrek en MHV van 85.7 cm en 0.89 en vroue 97.5 cm en 0.85, onderskeidelik gehad. Analise van die 24-uur dieetopname het baie lae gemiddelde energie innames getoon (M 6516 (2929; V 5760 (2446) kJ. Hierdie resultate het nie die hoë voorkoms van vetsug, veral in vroue, asook in vier ander studies onder stedelike swart bevolkings ondersteun nie. Gevolglik is die Goldberg vergelyking gebruik om onderrapporteurs uit te skakel. Die oorblywende steekproef het 544 (214 mans en 330 vroue) deelnemers behels wat te Khayelitsha (42.4%), Langa (31.4%), en Gugulethu (15.3%) woonagtig was, met minder as 10% te Crossroads en Nyanga. Na die uitskakeling van onderrapporteurs was die gemiddelde energie-innames soortgelyk aan dié van die 1990 studie, en in 25–44-jarige mans was dit 8557 kJ vergeleke met 8500 kJ in 1990. In vroue was dit 7619 kJ vergeleke met 6400 kJ in 1990. Vetinnames was die hoogste in die 25–44- jarige mans (32% energie [E]) en vroue (33.4% E) in 2009 vergeleke met 1990 (mans: 25.9% E, vroue: 27.0% E). Koolhidraatinnames was laer in 2009 (mans 53.2% E, vroue: 55.5% E) as in 1990 (mans: 61.3% E; vroue: 62% E), terwyl suikerinname in vroue betekenisvol (p <0.01) toegeneem het. Daar was betekenisvolle positiewe korrelasies tussen verstedeliking en totale vet (p=0.016), versadigde vet (p=0.001), mono-onversadigde vet (p=0.002) en vet as ’n %E inname (p=0.046). Verstedeliking was omgekeerd geassosieer met die inname van koolhidraat %E (p <0.001). Oor die algemeen het mikronutriëntinnames betekenisvol verbeter vergeleke met 1990 met die uitsondering van kalsiuminname. Hierdie is moontlik te wyte aan die nasionale fortifisering van mielies en volgraanmeel. Van belang is dat energie en makronutriëntinnames almal betekenisvol was, asook duur van verstedeliking, volgens ’n lineêre regressiemodel met behulp van die gemiddelde toereikendheidsverhouding. Die hoër vet en laer koolhidraat %E innames in hierdie bevolking demonstreer ’n oorgang na ’n meer verstedelikte dieet oor die twee dekades. Voorwaartse regressie is gedoen om betekenisvolle veranderlikes te identifiseer wat daarna in die lineêre regressiemodel ingesleutel is. In mans is LMI betekenisvol geassosieer met proteïeninname, terwyl in vroue LMI verband gehou het met versadigde vet, versadigde vet %E, koolhidraat, en koolhidraat %E. Ten opsigte van die duur van verstedeliking kan dit gemeld word dat koolhidraat %E totale vet %E energie, kalsium, dierproteïen en totale cholesterol betekenisvol geassosieer is met groter verstedeliking. In die 2009 studie is gevind dat melkprodukte, die vleisgroep, peulgewasse, versadigde vet en harde (volvet) margarien in mans en vroue statisties laer was as dié in die 1990 studie. Hierdie is ook vir die graangroep gevind, maar slegs vir mans. Ten spyte hiervan het die 2009 studie vir die mans en vroue betekenisvolle hoër innames getoon vir eiers, vitamien C-ryke vrugte en groente en polionversadigde vetsuurbronne vergeleke met die 1990 groep. Hierdie is ook vir die graangroep gevind vir vroue. Die persentasie verbruikers van rooivleis, witvleis, eiers, groente en vrugte, en graan het van 1990 tot 2009 toegeneem. Vir die suiwel- en vetgroepe het die persentasie verbruikers afgeneem. Gevolgtrekking: Die nutriëntinnames demonstreer dat terwyl sekere veranderinge tussen 1990 en 2009 plaasgevind het, die dieetpatroon aangaande voedselinname swak bly. Die dieet het meer verstedlik en aterogenies geword met betrekking tot vetverspreiding en koolhidraatinname, terwyl die verbruik van sekere voedselgroepe laag gebly het, soos die swak inname van suiwelprodukte en lae inname van vrugte en groente. Die algehele gemiddelde mikronutriëntinnames het egter toegeneem tot bokant die dieetverwysingsinnames, met die uitsondering van kalsiuminname. Aanbeveling: Intervensies is dringend nodig om die verskuiwing na ’n voortgesette aterogeniese dieet teen te werk en die verbruik van voorkeurvoedselgroepe, soos suiwelprodukte en vrugte en groente te bevorder.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/101440
This item appears in the following collections: