EAL

H/A: Micronutrient Supplementation (2009)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The aim of this study was to compare the serum protein and micronutrient status of HIV-positive and HIV-negative breastfeeding South African mothers during the first six months after delivery.

Inclusion Criteria:

Most of the mothers enrolled in the MN study were simultaneously participating in the Africa Centre Vertical Transmission (VT) study
The subjects included HIV-positive pregnant women living and attending antenatal clinics in the region and a time-related random sample of HIV-negative pregnant women attending the same clinics.

Exclusion Criteria:

Mothers who intended to return to school or work within two months of delivery or to leave the area within three months of delivery were excluded.

Description of Study Protocol:

Recruitment

Mothers were consecutively enrolled at one clinic in the peri-urban township and at two clinics in rural areas. Enrollment for the MN study began in May 2002, and the last six-month follow-up visit was completed in February 2004.

Design

This prospective longitudinal observation study measured select serum proteins, vitamins and minerals in clinic-attending HIV-positive and HIV-negative breastfeeding South African mothers between six and 24 weeks after delivery.

Blinding Used

The field and laboratory staff members were blinded to the participants' HIV status.

Statistical Analysis

Demographic and biochemical variables at each time point, differences between HIV-positive and HIV-negative:
- A chi-square test for categorical variables
- Student's T-test for continuous variables
Longitudinal measures (repeated measures mixed-model analysis of variance)
Covariates (age, number of previous pregnancies, years of education and clinic location)
Retinol distributions (C-square root transformation)
Nutrient (albumin, prealbumin, and all micronutrients), AGP or CRP from each time point was entered into a mixed model individually to explore interactions and significance; in addition, AGP or CRP from all three time points was entered together.

Data Collection Summary:

Timing of Measurements

The study participants were enrolled six weeks after delivery and had subsequent study visits at 14 and 24 weeks after delivery.

Dependent Variables

Demographics characteristics
Serum and plasma measures (CRP, AGP, albumin and prealbumin, Vitamin B₁₂, folate, retinol and tocopherol, serum ferritin, zinc, selenium and copper).

Independent Variables

HIV status.

Description of Actual Data Sample:

Initial N: 144 mothers were enrolled from clinics, of whom 92 were HIV-positive and 52 were HIV-negative. 24 mothers (21.7% of the HIV-positive women and 7.6% of the HIV-negative mothers; P=0.03) withdrew or were lost to follow-up before the six-month observation
Attrition (final N): 120 mothers
Age: The mothers were between 14 and 50 years of age; eight mothers were younger than 18 years of age and three were older than 40 years of age.
Ethnicity: South African women
Other relevant demographics: 35% of the mothers were primiparous
Anthropometrics: The demographic characteristics did not differ significantly between the HIV-positive and HIV-negative mothers
Location: Africa Centre for Health and Population Studies in northern KwaZulu-Natal Province, South Africa.

Summary of Results:

Other Findings

The mean alpha₁-acid glycoprotein (AGP) concentration was higher in the HIV-positive women than in the HIV-negative women and the percentage of HIV-positive mothers with an acute phase response was significantly higher than that of the HIV-negative mothers
Mean CRP concentrations tended to be higher in the HIV-positive than in the HIV-negative mothers, but the difference was not significant (P=0.075), and no significant difference in the proportion of HIV-positive and HIV-negative mothers with an acute phase response (i.e., CRP more than 5.0mg per L) was observed
Mean albumin and prealbumin were significantly lower in HIV-positive mothers, and a higher proportion of HIV-positive mothers had low albumin concentrations (less than 35g per L)
No significant differences in mean micronutrient status indicators were observed when mothers who reported ever taking supplements were compared with those who reported never taking supplements, regardless of HIV status; however, the power to detect differences was small
No significant differences in mean serum vitamin B₁₂ concentrations were observed between groups. Less than 45% of the mothers were vitamin B₁₂- or folate-sufficient. Significantly more HIV-positive (70.5%) than HIV-negative (46.2%) mothers had marginal vitamin B₁₂ status (P<0.05), and mean folate concentrations were lower in HIV-positive mothers (P=0.05).
The mean serum folate concentration was low (less than 14.0nmol per L) in both groups and was significantly lower in the HIV-positive mothers
Mean serum retinol was significantly lower in HIV-positive mothers, even after control for the acute phase response
At 24 weeks, 70% of both groups had an alpha-tocopherol deficiency (less than 11.6 µmol per L), but no significant difference by HIV status was observed
More HIV-positive (33.3%) than HIV-negative (8.7%) mothers had anemia (P=0.018), whereas 25% of all mothers had low serum ferritin concentrations
After the acute phase response was controlled, zinc deficiency was more common in HIV-positive (45.0%) than in HIV-negative (25.0%) mothers (P=0.05).

Author Conclusion:

Authors found that a large proportion of clinic-attending breastfeeding women in rural South Africa had multiple nutrient deficiencies (vitamins B₁₂, folate, alpha-tocopherol, ferritin and zinc), which can affect both their health and that of their infants. Second, and perhaps more important, deficiencies of protein, zinc, iron, and vitamins A and B₁₂ and were more common and severe in HIV-positive mothers, although reverse causality was a possibility.

Funding Source:

Government:

National Institute of Allergy and Infectious Diseases

Industry:

Reviewer Comments:

Authors note the following limitations:

Researchers would have preferred to compare the nutrient status between HIV-positive breastfeeding and non-breastfeeding women
Six of the mothers in the HIV-negative group were reassigned to the HIV-positive group
Results may only be generalizable to the "well" population of HIV-positive breastfeeding women.

Quality Criteria Checklist: Primary Research
Relevance Questions
	1.	Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)	Yes
	2.	Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?	Yes
	3.	Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?	Yes
	4.	Is the intervention or procedure feasible? (NA for some epidemiological studies)	Yes

Validity Questions
1.	Was the research question clearly stated?		Yes
	1.1.	Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?	Yes
	1.2.	Was (were) the outcome(s) [dependent variable(s)] clearly indicated?	Yes
	1.3.	Were the target population and setting specified?	Yes
2.	Was the selection of study subjects/patients free from bias?		Yes
	2.1.	Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	2.4.	Were the subjects/patients a representative sample of the relevant population?	Yes
3.	Were study groups comparable?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	???
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	3.3.	Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)	N/A
	3.4.	If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?	Yes
	3.5.	If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)	N/A
	3.6.	If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?	N/A
4.	Was method of handling withdrawals described?		Yes
	4.1.	Were follow-up methods described and the same for all groups?	???
	4.2.	Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)	Yes
	4.3.	Were all enrolled subjects/patients (in the original sample) accounted for?	Yes
	4.4.	Were reasons for withdrawals similar across groups?	Yes
	4.5.	If diagnostic test, was decision to perform reference test not dependent on results of test under study?	N/A
5.	Was blinding used to prevent introduction of bias?		Yes
	5.1.	In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?	N/A
	5.2.	Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)	N/A
	5.3.	In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?	Yes
	5.4.	In case control study, was case definition explicit and case ascertainment not influenced by exposure status?	N/A
	5.5.	In diagnostic study, were test results blinded to patient history and other test results?	N/A
6.	Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?		Yes
	6.1.	In RCT or other intervention trial, were protocols described for all regimens studied?	N/A
	6.2.	In observational study, were interventions, study settings, and clinicians/provider described?	Yes
	6.3.	Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?	Yes
	6.4.	Was the amount of exposure and, if relevant, subject/patient compliance measured?	N/A
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	6.6.	Were extra or unplanned treatments described?	N/A
	6.7.	Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?	N/A
	6.8.	In diagnostic study, were details of test administration and replication sufficient?	N/A
7.	Were outcomes clearly defined and the measurements valid and reliable?		Yes
	7.1.	Were primary and secondary endpoints described and relevant to the question?	Yes
	7.2.	Were nutrition measures appropriate to question and outcomes of concern?	Yes
	7.3.	Was the period of follow-up long enough for important outcome(s) to occur?	Yes
	7.4.	Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	8.3.	Were statistics reported with levels of significance and/or confidence intervals?	Yes
	8.4.	Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?	N/A
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	8.6.	Was clinical significance as well as statistical significance reported?	Yes
	8.7.	If negative findings, was a power calculation reported to address type 2 error?	N/A
9.	Are conclusions supported by results with biases and limitations taken into consideration?		Yes
	9.1.	Is there a discussion of findings?	Yes
	9.2.	Are biases and study limitations identified and discussed?	Yes
10.	Is bias due to study's funding or sponsorship unlikely?		Yes
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	Yes