PubMed Health⌕ Search

Biomedical subjects

Andrew M Prentice

Publications and source records attributed to Andrew M Prentice.

27 records · Page 2Linked to original sources
PubMed2004

Comparative analysis of patterns of survival by season of birth in rural Bangladeshi and Gambian populations.

BACKGROUND: Analysis of data from rural Gambia has previously shown that being born during the annual hungry season strongly influences susceptibility to mortality from infectious disease in young adulthood, possibly through an influence on immune function. In rural Bangladesh pregnancies are exposed to similar seasonality. The current paper uses data from a large demographic survey in the Matlab region of Bangladesh to retest the Gambian-derived hypothesis that early life exposures correlated with season of birth predict later patterns of mortality. METHODS: Since 1966, a continuous demographic surveillance system has been in operation in the rural Matlab region of Bangladesh. The current analysis is based on 172 228 births and 24 697 deaths between 1974 and 2000. Season of birth was defined as 'harvest' (January-June) and 'hungry' (July-December), based on monthly variations in rates of conception and neonatal mortality within the same dataset. RESULTS: Birth during the hungry season resulted in excess mortality during the first year of life. However, for adult mortality (deaths >15 years), there was no excess in individuals born during the annual hungry season: ratio of hazard July-December versus January-June = 1.12; 95% CI: 0.87, 1.45. CONCLUSIONS: The current study found no excess mortality in young adults born during the 'hungry' season in rural Bangladesh. This differing pattern in survival when compared with The Gambia may be a consequence of the greatly reduced incidence of young adult deaths in Bangladesh (0.1%) compared with The Gambia (3%). Under such conditions possible differences in immune function may not be detectable with early adult death as the outcome. However, it also remains possible that our Gambian observation could be a highly discrete phenomenon localized in either time or place, and as such, will not be replicated in other populations.

Adolescent↗
PubMed2004

Fifty-year mortality trends in three rural African villages.

OBJECTIVE: To determine differential improvements in mortality rates according to age, and to discuss differences in neonatal and post-neonatal mortality rates, using longitudinal data from the past 50 years in three rural Gambian villages. METHODS: All villagers whose date of birth was recorded were followed up until death or October 1997. A Lexis expansion was performed to categorize age: early neonatal, late neonatal, infant, 1-4 years, 5-14 years and 15 or more years. Calendar time was divided into three periods -- prior to 1975, 1975-1984 and after 1985, representing different levels of clinical care. Cox regression and likelihood-ratio test were used to model the hazards ratios. RESULTS: There were 3981 subjects included in the analysis with a total of 59 002 person-years follow-up. There was a dramatic decrease in neonatal (44 to 15), infant (162 to 36) and under-five mortality rates (397-66 per 1000) from pre-1975 to the present. The disproportionate decrease in the mortality rates means that neonatal deaths accounted for a greater percentage of post-natal deaths in later years. There was a marked seasonality in mortality rates with significantly more deaths in the 'hungry' season prior to 1975 (odds = 1.87; 95% CI = 1.62-2.17) and from 1975 to 1984 (odds = 1.84; 95% CI = 1.34-2.53). This seasonality of death has diminished in recent years (odds = 1.23; 95% CI = 0.85-1.76). CONCLUSION: Our analysis indicates a dramatic reduction in mortality rates and an attenuation in the seasonality of death. It is likely that the efficient implementation of basic currently available health measures was one of the key elements in achieving such a major reduction in mortality.

Adolescent↗
PubMed2003

Modification of immune function through exposure to dietary aflatoxin in Gambian children.

Aflatoxins are immunotoxins that frequently contaminate staple foods in The Gambia and other parts of sub-Saharan Africa, resulting in high exposure throughout life. Impaired infant immune system development may be a key predictor of mortality from infectious disease. In this study we aimed to determine the effect of dietary aflatoxin exposure on a number of immune parameters in Gambian children. A cohort of 472 Gambian children 6-9 years of age was recruited. Serum aflatoxin-albumin (AF-alb) adducts were analyzed to provide a measure of exposure. Immune parameters included secretory IgA (sIgA) in saliva, cell-mediated immunity (CMI), determined using the CMI multitest where test antigens are applied to the skin, and antibody responses to both rabies and pneumococcal polysaccharide vaccines. Birth weight, current anthropometry, and micronutrient status were also recorded. AF-alb adducts were detected in 93% of the children (geometric mean level 22.3 pg/mg; range 5-456 pg/mg). AF-alb level was strongly influenced by month of sampling. In a multivariable analysis, sIgA was markedly lower in children with detectable AF-alb compared with those with nondetectable levels [50.4 micro g/mg protein (95% confidence interval [CI] 48.0-52.8) and 70.2 micro g/mg protein (95% CI 61.1-79.2), respectively; p < 0.0001]. Antibody response to one of four pneumococcal serotypes, but not rabies vaccine, was weakly associated with higher levels of AF-alb. There was no association between CMI responses to test antigens and AF-alb. These data confirm that children in rural Gambia are frequently exposed to high levels of aflatoxin. The study provides evidence that sIgA in saliva may be reduced because of dietary levels of aflatoxin exposure. Given the high burden of infection-related mortality in West Africa, further investigation of the immune effects of aflatoxin exposure in children is merited.

Aflatoxins↗
PubMed2002

[The CARMEN trial: increased intake of carbohydrates--simple or complex--and unchanged blood lipids in overweight subjects].

INTRODUCTION: The purpose was to investigate the long-term effect of ad libitum low-fat, high-carbohydrate diets with mainly simple or complex carbohydrates on body weight and blood lipids. MATERIAL AND METHODS: A six-months controlled randomised multicentre trial with the participation of five European centres. A total of 398 moderately obese subjects (BMI: 30.4 +/- 2.7 kg/m2, mean +/- SD) were randomised to four groups: Control diet group with normal macronutrient intake, a low-fat/high simple carbohydrate group, a low-fat/high complex carbohydrate group and a seasonal control group. RESULTS: After six months we found a drop in body weight of 1.7 kg (p < 0.05) in the simple and of 2.6 kg (p < 0.001) in the complex carbohydrate group compared with the control diet group. Fat mass decreased by 1.9 kg (p < 0.05) and 2.4 kg (p < 0.001) in the simple and complex carbohydrate group, respectively, compared with the control diet group. There were no significant changes or group differences in fasting blood lipids, glucose, insulin, or leptin. DISCUSSION: The results show that it is favourable to replace dietary fat by carbohydrates (simple or complex) in relation to body weight regulation. No detrimental effects were seen on blood lipids in contrast to previous contentions. Our results underline the importance of a low-fat/high-carbohydrate diet in the management of obesity and the ensuing health problems.

Adult↗
PubMed2002

Long-term effects of ad libitum low-fat, high-carbohydrate diets on body weight and serum lipids in overweight subjects with metabolic syndrome.

BACKGROUND: Overweight individuals with metabolic syndrome are at increased risk of type 2 diabetes and coronary vascular disease. Weight gain and features of the syndrome may be ameliorated by dietary intervention. OBJECTIVE: We investigated the effects of replacing one-quarter of daily fat intake by complex or simple carbohydrate on body weight and intermediary metabolism. DESIGN: Forty-six subjects with > or =3 metabolic syndrome risk factors were randomly assigned to receive a control diet; a low-fat, complex carbohydrate diet (LF-CC); or a low-fat, simple carbohydrate diet (LF-SC) for 6 mo. Thirty-nine subjects completed the trial. About 60% of daily dietary intake was provided free of charge through a grocery store. Energy intake was ad libitum. Body weight, body mass index (BMI), blood pressure, and blood lipids were measured at months 0, 2, 4, and 6. RESULTS: There was a significant diet x time interaction on body weight and BMI (P < 0.001). Weight loss was greatest with the LF-CC diet [change in body weight: control diet, 1.03 kg (NS); LF-CC diet, -4.25 kg (P < 0.01); LF-SC diet, -0.28 kg (NS)]. Total cholesterol decreased by 0.33 mmol/L, 0.63 mmol/L, and 0.06 mmol/L in subjects consuming the control, LF-CC, and LF-SC diets, respectively (difference between the LF-CC and LF-SC groups: P < 0.05). There were no significant changes in LDL cholesterol, whereas HDL cholesterol decreased over time in all 3 groups (P < 0.0001). Triacylglycerol concentrations were higher in the LF-SC group than in the other 2 groups (P < 0.05). CONCLUSIONS: A low-fat, high-polysaccharide diet in overweight individuals with abnormal intermediary metabolism led to moderate weight loss and some improvement in serum cholesterol. Increasing simple carbohydrates did not promote weight gain, but nor was there improvement in body weight or lipid profile.

Adult↗