Female rats consuming an iron and omega-3 fatty acid deficient diet preconception require combined iron and omega-3 fatty acid supplementation for the prevention of bone impairments in offspring.

We previously showed in rats that pre- and postnatal deficiencies in iron and omega-3 (n-3) fatty acids can impair bone development, with additive and potentially irreversible effects when combined. This study aimed to investigate, in female rats consuming a combined iron and n-3 fatty acid deficient (ID + n-3 FAD) diet preconception, whether supplementation with iron and docosahexaenoic/eicosapentaenoic acid (DHA/EPA), alone and in combination, can prevent bone impairments in offspring. Using a 2 × 2 factorial design, female Wistar rats consuming an ID + n-3 FAD diet preconception were randomised to receive an: 1) iron supplemented (Fe + n-3 FAD), 2) DHA/EPA supplemented (ID + DHA/EPA), 3) Fe + DHA/EPA, or 4) ID + n-3 FAD diet from gestational day 10 throughout pregnancy and lactation. Post-weaning, offspring (n = 24/group; male:female = 1:1) remained on the respective experimental diets for three weeks until postnatal day 42-45. Offspring born to female rats consuming a control diet preconception and an Fe+DHA/EPA diet throughout pregnancy and lactation served as non-deficient reference group (Control+Fe+DHA/EPA). Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry and bone strength using three-point bending tests. Only offspring in the Fe+DHA/EPA group had significantly higher spine and femur BMD, and higher femur stiffness than offspring in the ID + n-3 FAD group, and had similar spine BMD and femur stiffness as the Control + Fe + DHA/EPA group. Offspring in the Fe + DHA/EPA group further had significantly higher femur strength (ultimate load) than the other experimental groups, and a similar femur strength as the Control + Fe + DHA/EPA group. This study shows that only combined iron and DHA/EPA supplementation can prevent bone impairments in offspring of female rats consuming an iron and n-3 FA deficient diet preconception.

Strategies of Modelling Incident Outcomes Using Cox Regression to Estimate the Population Attributable Risk.

When the Cox model is applied, some recommendations about the choice of the time metric and the model's structure are often disregarded along with the proportionality of risk assumption. Moreover, most of the published studies fail to frame the real impact of a risk factor in the target population. Our aim was to show how modelling strategies affected Cox model assumptions. Furthermore, we showed how the Cox modelling strategies affected the population attributable risk (PAR). Our work is based on data collected in the North-West Province, one of the two PURE study centres in South Africa. The Cox model was used to estimate the hazard ratio (HR) of mortality for all causes in relation to smoking, alcohol use, physical inactivity, and hypertension. Firstly, we used a Cox model with time to event as the underlying time variable. Secondly, we used a Cox model with age to event as the underlying time variable. Finally, the second model was implemented with age classes and sex as strata variables. Mutually adjusted models were also investigated. A statistical test to the multiplicative interaction term the exposures and the log transformed time to event metric was used to assess the proportionality of risk assumption. The model's fitting was investigated by means of the Akaike Information Criteria (AIC). Models with age as the underlying time variable with age and sex as strata variables had enhanced validity of the risk proportionality assumption and better fitting. The PAR for a specific modifiable risk factor can be defined more accurately in mutually adjusted models allowing better public health decisions. This is not necessarily true when correlated modifiable risk factors are considered.

Medications for blood pressure, blood glucose, lipids, and anti-thrombotic medications: relationship with cardiovascular disease and death in adults from 21 high-, middle-, and low-income countries with an elevated body mass index.

AIMS: Elevated body mass index (BMI) is an important cause of cardiovascular disease (CVD). The population-level impact of pharmacologic strategies to mitigate the risk of CVD conferred by the metabolic consequences of an elevated BMI is not well described. METHODS AND RESULTS: We conducted an analysis of 145 986 participants (mean age 50 years, 58% women) from 21 high-, middle-, and low-income countries in the Prospective Urban and Rural Epidemiology study who had no history of cancer, ischaemic heart disease, heart failure, or stroke. We evaluated whether the hazards of CVD (myocardial infarction, stroke, heart failure, or cardiovascular death) differed among those taking a cardiovascular medication (n = 29 174; including blood pressure-lowering, blood glucose-lowering, cholesterol-lowering, or anti-thrombotic medications) vs. those not taking a cardiovascular medication (n = 116 812) during 10.2 years of follow-up. Cox proportional hazard models with the community as a shared frailty were constructed by adjusting age, sex, education, geographic region, physical activity, tobacco, and alcohol use. We observed 7928 (5.4%) CVD events and 9863 (6.8%) deaths. Cardiovascular medication use was associated with different hazards of CVD (interaction P < 0.0001) and death (interaction P = 0.0020) as compared with no cardiovascular medication use. Among those not taking a cardiovascular medication, as compared with those with BMI 20 to <25 kg/m2, the hazard ratio (HR) [95% confidence interval (95% CI)] for CVD were, respectively, 1.14 (1.06-1.23); 1.45 (1.30-1.61); and 1.53 (1.28-1.82) among those with BMI 25 to <30 kg/m2; 30 to <35 kg/m2; and ≥35 kg/m2. However, among those taking a cardiovascular medication, the HR (95% CI) for CVD were, respectively, 0.79 (0.72-0.87); 0.90 (0.79-1.01); and 1.14 (0.98-1.33). Among those not taking a cardiovascular medication, the respective HR (95% CI) for death were 0.93 (0.87-1.00); 1.03 (0.93-1.15); and 1.44 (1.24-1.67) among those with BMI 25 to <30 kg/m2; 30 to <35 kg/m2; and ≥35 kg/m2. However, among those taking a cardiovascular medication, the respective HR (95% CI) for death were 0.77 (0.69-0.84); 0.88 (0.78-0.99); and 1.12 (0.96-1.30). Blood pressure-lowering medications accounted for the largest population attributable benefit of cardiovascular medications. CONCLUSION: To the extent that CVD risk among those with an elevated BMI is related to hypertension, diabetes, and an elevated thrombotic milieu, targeting these pathways pharmacologically may represent an important complementary means of reducing the CVD burden caused by an elevated BMI.

Lifestyle factors associated with the transition from healthy to unhealthy adiposity among black South African adults over 10 years.

BACKGROUND AND AIMS: Obesity is associated with an increasing prevalence of cardiovascular diseases in Africa, but some obese individuals maintain cardiometabolic health. The aims were to track metabolically healthy overweight or obesity (MHO) over 10 years in African adults and to identify factors associated with a transition to metabolically unhealthy overweight or obesity (MUO). METHODS AND RESULTS: The participants were the South African cohort of the international Prospective Urban and Rural Epidemiological study. From the baseline data of 1937 adults, 649 women and 274 men were followed for 10 years. The combined overweight and obesity prevalence of men (19.2%-23.8%, p = .02) and women (58%-64.7%, p < .001), and the prevalence of the metabolic syndrome in all participants (25.4%-40.2%, p < .001) increased significantly. More than a quarter (26.2%) of the women and 10.9% of men were MHO at baseline, 11.4% of women and 5.1% of men maintained MHO over 10 years, while similar proportions (12.3% of women, 4.7% of men) transitioned to MUO. Female sex, age, and total fat intake were positively associated with a transition to MUO over 10 years, while physical activity was negatively associated with the transition. HIV positive participants were more likely to be MHO at follow-up than their HIV negative counterparts. CONCLUSIONS: One in two black adults with BMI ≥25 kg/m2 maintained MHO over 10 years, while a similar proportion transitioned into MUO. Interventions should focus on lower fat intakes and higher physical activity to prevent the transition to MUO.

The Relationship of Circulating Homocysteine with Fibrinogen, Blood Pressure, and Other Cardiovascular Measures in African Adolescents.

OBJECTIVES: To evaluate the associations between homocysteine (Hcy) and cardiovascular health in South African adolescents. STUDY DESIGN: Circulating Hcy concentrations of 172 South African adolescents (105 girls, ages 13 to <18 years) were measured. Anthropometric and cardiovascular factors were also included and cross-sectionally analyzed through general linear models. RESULTS: Hcy correlated positively with body weight (P = .03; after adjusting for multiple testing, it was not regarded as significant) and muscle mass (P = .01), but negatively with fibrinogen concentrations (P = .001). Across Hcy tertiles, blood pressure produced approximating U-shaped curves, with differences between the middle and upper tertiles (all P < .02). Forty percent of the adolescents had elevated blood pressure, of whom 37% fell in the lowest and 38% in the highest Hcy tertiles. Hcy differed between the sexes (with boys having higher Hcy), but not between subgroups based on puberty, weight, stunting, smoking, or alcohol consumption. CONCLUSIONS: Both high and low Hcy could be early contributing risk factors to cardiovascular health. The associations between Hcy and blood pressure suggest that dietary and lifestyle manipulation, to achieve the optimal range of Hcy, may be beneficial in preventing Hcy-related hypertension in adulthood. The inverse relationship between Hcy and fibrinogen remains to be clarified.

Effects and Reversibility of Pre- and Post-natal Iron and Omega-3 Fatty Acid Deficiency, Alone and in Combination, on Bone Development in Rats.

Both iron and omega-3 (n-3) polyunsaturated fatty acids may play an important role in bone development. The aim of this study was to investigate the effects of pre- and post-natal iron and n-3 fatty acid deficiency (FAD), alone and in combination, on bone development in rats, and to determine whether effects are reversible when a sufficient diet is provided post-weaning. Using a 2×2-factorial design, 56 female Wistar rats were allocated to one of four diets: (1) control, (2) iron deficient (ID), (3) n-3 FAD or (4) ID and n-3 FAD, and were maintained on the respective diets throughout gestation and lactation. At weaning (post-natal day [PND] 21), offspring (n = 24/group; male:female=1:1) were randomly allocated to either continue with their respective diets or to switch to the control diet until PND 42-45. Bone mineral density (BMD) and bone strength were determined using dual X-ray absorptiometry and three-point bending tests, respectively. Pre- and post-natal ID resulted in significantly lower BMD in the spine and bone strength in the left femur. Both ID and n-3 FAD resulted in lower BMD in the right femur, with an additive reduction in the combined ID and n-3 FAD group vs. controls. While negative effects of pre- and post-natal ID alone were reversed in offspring switched to a control diet post-weaning, lower BMD and bone strength persisted in offspring with combined ID and n-3 FAD during the prenatal and early post-natal period. Effects were not sex-specific. These results indicate that ID during early life may negatively influence bone development, with potential additive effects of n-3 FAD. While the effects of ID alone seem reversible, a combined ID and n-3 FAD may result in irreversible deficits in bone development.

Effect of small-quantity lipid-based nutrient supplements on growth, psychomotor development, iron status, and morbidity among 6- to 12-mo-old infants in South Africa: a randomized controlled trial.

Background: Evidence on the effect of small-quantity lipid-based nutrient supplements (SQ-LNSs) on early child growth and development is mixed. Objective: This study assessed the effect of daily consumption of 2 different SQ-LNS formulations on linear growth (primary outcome), psychomotor development, iron status (secondary outcomes), and morbidity in infants from age 6 to 12 mo within the context of a maize-based complementary diet. Methods: Infants (n = 750) were randomly assigned to receive SQ-LNS, SQ-LNS-plus, or no supplement. Both SQ-LNS products contained micronutrients and essential fatty acids. SQ-LNS-plus contained, in addition, docosahexaenoic acid, arachidonic acid (important for brain and eye development), lysine (limiting amino acid in maize), phytase (enhances iron absorption), and other nutrients. Infants' weight and length were measured bimonthly. At age 6 and 12 mo, psychomotor development using the Kilifi Developmental Inventory and South African Parent Rating Scale and hemoglobin, plasma ferritin, C-reactive protein, and α1-acid glycoprotein were assessed. WHO Motor Milestone outcomes, adherence, and morbidity were monitored weekly through home visits. Primary analysis was by intention-to-treat, comparing each SQ-LNS group with the control. Results: SQ-LNS-plus had a positive effect on length-for-age zscore at age 8 mo (mean difference: 0.11; 95% CI: 0.01, 0.22; P = 0.032) and 10 mo (0.16; 95% CI: 0.04, 0.27; P = 0.008) but not at 12 mo (0.09; 95% CI: -0.02, 0.21; P = 0.115), locomotor development score (2.05; 95% CI: 0.72, 3.38; P = 0.003), and Parent Rating Score (1.10; 95% CI: 0.14, 2.07; P = 0.025), but no effect for weight-for-age zscore. Both SQ-LNS (P = 0.027) and SQ-LNS-plus (P = 0.005) improved hemoglobin concentration and reduced the risk of anemia, iron deficiency, and iron-deficiency anemia. Both SQ-LNS products reduced longitudinal prevalence of fever, coughing, and wheezing but increased incidence and longitudinal prevalence of diarrhea, vomiting, and rash/sores. Conclusions: Point-of-use fortification with SQ-LNS-plus showed an early transient effect on linear growth and improved locomotor development. Both SQ-LNS products had positive impacts on anemia and iron status. This trial was registered at clinicaltrials.gov as NCT01845610.

Differential ferritin interpretation methods that adjust for inflammation yield discrepant iron deficiency prevalence.

We reassessed the iron deficiency (ID) prevalence in a South African trial that formed part of the International Research on Infant Supplementation study by comparing four methods that account for the high prevalence of acute (28.6%) and chronic (41.8%) inflammation observed in the study. Serum ferritin (SF) was measured as marker of iron status in 192 apparently healthy, 4-13-month-old infants. Alpha-1 glycoprotein and C-reactive protein concentrations were determined to indicate chronic and acute inflammation, respectively. The ID prevalence was obtained by four methods that adjust for inflammation: (1) excluding infants with inflammation; (2) using a higher cut-off (SF < 30 µg L(-1) ); (3) using different cut-offs for infants with vs. without inflammation (SF < 30 µg L(-1) vs. SF < 12 µg L(-1) ); and (4) adjusting SF concentrations with correction factors (CFs) were compared with a reference method (SF < 12 µg L(-1) ) not accounting for inflammation. Using the higher SF cut-off method resulted in the highest ID prevalence (52.1%), followed by using two different cut-offs (31.8%), using CFs (21.9%) and excluding subjects with inflammation (17.6%). The CF method showed the best agreement with the reference method. Disregarding inflammation resulted in a significantly lower ID prevalence (17.2%). ID anaemia (IDA) prevalence ranged from 13.2% to 24.5%, with the lowest prevalence (12.0%) for the reference method. Our analysis highlights the challenge of assessing ID and IDA using only SF as marker of iron status in the presence of inflammation. We demonstrate the importance of measuring inflammation markers to account for their elevating effect on SF.

Positive association between dietary iron intake and iron status in HIV-infected children in Johannesburg, South Africa.

Anemia is a common complication of pediatric HIV infection and is associated with suboptimal cognitive performance and growth failure. Routine iron supplementation is not provided to South African HIV-infected children. We hypothesized that dietary iron intake without supplementation is sufficient to protect against iron deficiency (ID) in HIV-infected children receiving highly active antiretroviral therapy. In this prospective study, the difference between dietary intakes of iron-deficient children (soluble transferrin receptor >9.4 mg/L) and iron-sufficient children after 18 months on highly active antiretroviral therapy was examined. The association between iron intake and hemoglobin (Hb) concentration was also assessed. Longitudinal data collected for 18 months from 58 HIV-infected African children were assessed by generalized estimation equations, with adjustment for demographic information, dietary intakes, growth parameters, and CD4%. After adjustment for covariates, the longitudinal association between dietary iron intake and Hb concentration remained significant. This association shows that for every 1-mg increase in iron intake per day, Hb increases by 1.1 g/L (P < .001). Mean Hb increased significantly after 18 months of follow-up (106 ± 14 to 129 ± 14 g/L, P < .01), but soluble transferrin receptor also increased (7.7 ± 2.7 to 8.9 ± 3.0 mg/L, P < .01). The incidence of ID increased from 15.2% at baseline to 37.2% after 18 months. Children with animal protein intakes greater than >20 g/d had significantly lower odds for ID at 18 months than did children with lower intakes (odds ratio, 0.40; 95% confidence interval, 0.21-0.77). Dietary iron intake was insufficient to protect against ID, pointing to a need for low-dose iron supplementation for iron-deficient HIV-infected children and interventions to increase the consumption of animal protein.