PubMed Health⌕ Search

Biomedical subjects

C Rotimi

Publications and source records attributed to C Rotimi.

At least 19 recordsLinked to original sources
PubMed2006

Agouti-related protein promoter variant associated with leanness and decreased risk for diabetes in West Africans.

OBJECTIVE: The role of the central melanocortin system in the development of obesity has been extensively studied. Single-nucleotide polymorphisms (SNPs) within several candidate genes have been associated with food intake and obesity-related phenotypes; however, few of these associations have been replicated. SNPs in the agouti-related protein (AGRP) gene coding (Ala67Thr, 199G/A) and promoter (-38C/T) have been reported to be associated with body mass index (BMI), fat mass (FM) and percent body fat, in populations of European and African descent. In this study, we evaluated the association between the functional AGRP -38C/T promoter SNP and weight-related traits, namely BMI, FM and fat-free mass (FFM), as well as diabetes status. DESIGN: An association study of the AGRP -38C/T SNP and indices of obesity and diabetes status. SUBJECTS: A well-characterized population of 538 West Africans from Ghana and Nigeria recruited in the AADM (Africa America Diabetes Mellitus) study (mean age 52 years, 41.3% males, 71% diabetic). MEASUREMENTS: Genotyping of the AGRP -38C/T SNP, BMI, FM, FFM and fasting plasma glucose. RESULTS: Women carrying two copies of the variant T allele had significantly lower BMI (OR=0.47; 95% CI, 0.25-0.87). Also, men with at least one copy of the variant T allele were over two times less likely to be diabetic than other men (OR=0.44; 95% CI, 0.22-0.89). CONCLUSION: Our results replicate previous findings and implicate the AGRP -38C/T SNP in the regulation of body weight in West Africans.

Agouti Signaling Protein↗
PubMed2005

A genome-wide scan for quantitative trait loci linked to obesity phenotypes among West Africans.

OBJECTIVE: To identify quantitative trait loci (QTL) for three obesity phenotypes: body mass index (BMI), fat mass (FM) and percent body fat (PBF) in West Africans with type 2 diabetes (T2DM). DESIGN: An affected sibling pair (ASP) design, in which both siblings had T2DM. Obesity was analyzed as a quantitative trait using a variance components approach. SUBJECTS: Sib-pairs affected with T2DM from the Africa America Diabetes Mellitus (AADM) study, comprising 321 sibling pairs and 36 half-sibling pairs. MEASUREMENTS: Weight was measured on an electronic scale to the nearest 0.1 kg, and height was measured with a stadiometer to the nearest 0.1 cm. Body composition was estimated using bioelectric impedance analysis (BIA). Genotyping was carried out at the Center for Inherited Disease Research (CIDR) with a panel of 390 trinucleotide and tetranucleotide repeats. RESULTS: The obesity-related phenotype showing the strongest linkage evidence was PBF on chromosome 2 (LOD 3.30 at 72.6 cM, marker D2S739). Suggestive linkage to FM was found on chromosomes 2 (LOD 2.56 at 80.4 cM) and 5 (LOD 2.25 at 98 cM, marker D5S1725). The highest LOD score for BMI was 1.68 (chromosome 4, 113.8 cM). The areas of linkage for the three phenotypes showed some clustering as all three phenotypes were linked to the same regions of 2p13 and 5q14, and our study replicated linkage evidence for several regions previously reported in other studies. CONCLUSION: We obtained evidence for several QTLs on chromosome 2, 4 and 5 to three obesity phenotypes. This study provides data on the genetics of obesity in populations that are currently under represented in the global effort directed at understanding the pathophysiology of excess adiposity in free living individuals.

Adipose Tissue↗
PubMed2004

Using verbal autopsy to identify and proportionally assign cause of death in Ibadan, southwest Nigeria.

Reliable and accurate data remain scarce on the cause and rates of mortality among adults in sub-Saharan Africa. The Idikan Adult Mortality Study, a prospective community-based study was initiated in order to obtain the overall as well as cause-specific mortality data for a community of adults (15 years and above). Standardised verbal autopsy questionnaire was used to investigate and assign the mode and cause of death. There were 232 reported deaths in the baseline population of 4127 adults over 5 years, giving an unadjusted death rate of 11.2 per 1000 per year. Thirty-nine (16.8% ) of these death occurred suddenly. The commonest known cause of death was due to cardiovascular disease, which was responsible for 43 (18.5% ) of all deaths. It was also the commonest known cause of sudden death accounting for 30.8% of such deaths. Infection was responsible for 28 (12.1% ) deaths while injury accounted for 7 (2.6% ) deaths. Subjects, 50 years and above were more likely to die and also die suddenly than were the younger subject (p<0.0001, p<0.0001) and significantly more death occurred in males than females (6.9% versus 4.7% ) (P<0.01). Deaths were also more likely to have occurred at home and outside the hospital, increasing the probability of these deaths being underreported. Following multivariate logistic regression analysis, respondents between the age of 20 -49 years had significantly reduced risk of dying (p=0.029), while cigarette smoking significantly increased the risk of dying (p=0.012). In the absence of the urgently needed vital statistics, use of verbal autopsies is a potentially useful investigative method for identifying and assigning cause of adult deaths in a community.

Adolescent↗
PubMed2001

Ethical challenges in community-based research.

Investigators in population-based studies confront unique ethical challenges due to the community context of their research, their methods of inquiry, and the implications of their findings for social groups. Issues surrounding requirements for informed consent, the protection of privacy and confidentiality, and relationships between investigators and participants take on greater complexity and have significance beyond the individual research subject. In this paper, ethical challenges associated with community-based epidemiological research are briefly examined. We argue that ethically responsible population-based studies must seriously consider community needs and priorities and that researchers should work collaboratively with local populations to implement study goals. Strategies that promote respect for populations in community-based studies are outlined. These include community participation in research development, implementation and interpretation; adequate provision of information about study objectives to community members; and systematic feedback of study results.

Bioethical Issues↗
PubMed2001

Ethical challenges in community-based research.

Investigators in population-based studies confront unique ethical challenges due to the community context of their research, their methods of inquiry, and the implications of their findings for social groups. Issues surrounding requirements for informed consent, the protection of privacy and confidentiality, and relationships between investigators and participants take on greater complexity and have significance beyond the individual research subject. In this paper, ethical challenges associated with community-based epidemiological research are briefly examined. We argue that ethically responsible population-based studies must seriously consider community needs and priorities and that researchers should work collaboratively with local populations to implement study goals. Strategies that promote respect for populations in community-based studies are outlined. These include community participation in research development, implementation and interpretation; adequate provision of information about study objectives to community members; and systematic feedback of study results.

Bioethical Issues↗
PubMed2000

Genetic inheritance of body mass index in African-American and African families.

Numerous studies have shown recessive major gene inheritance of body mass index (BMI) in white populations; few have examined the inheritance of BMI in the African-American population where obesity is more prevalent, nor in African populations where obesity is comparatively rare. To evaluate the inheritance of obesity in two different populations of African origin, we used segregation analysis to determine the transmission of BMI in 95 African-American families and 400 Nigerian families. Probands were selected from participants in the population-based International Collaborative Study on Hypertension in Blacks. Using class D regressive models, results from the segregation analysis of the African-American data showed evidence of a major gene effect on BMI. The Nigerian results were strikingly similar, with comparable estimates for the genotype frequencies and means and strong evidence for a major effect in the transmission of BMI. The high BMI allele frequency estimate of 24% is consistent with estimates in other studies, but the mode of transmission appeared codominant, which differs from studies involving predominantly white populations. In the Nigerian analysis, however, the probability of a high BMI homozygote parent transmitting a low BMI allele to his/her offspring was significantly different from the Mendelian expectation of zero (estimated tau(BB) = 0.45), suggesting that additional complexities exist in the major gene inheritance of BMI in this population. The strong similarity of the genotype frequencies and means obtained from the African-American and Nigerian samples suggests that a common codominant major gene effect may contribute to the variation in BMI in both populations.

Alleles↗
PubMed2000

The Idikan adult mortality study.

The Idikan adult mortality study is designed to explore the usefulness of the verbal autopsy methodology in the determination of cause-specific adult mortality. Such data have been largely unavailable in developing countries. Members of a stable urban community (4333 adults) were registered in their family units and followed up every 3 months to ascertain deaths, exits and new entries to the study population. Deaths were investigated by means of a verbal autopsy, which was administered by a trained interviewer to the relative closest to the decedent. Two physicians independently studied the results and assigned a cause of death, and these were then confirmed or resolved by a senior physician colleague. Hospitals where deaths occurred were visited and assignable cause of death was obtained where available and compared with the cause assigned by verbal autopsy. Only 8 of the 60 investigated deaths were confirmed to have occurred in a hospital in the first 2 years of the study. The cause of death assigned by verbal autopsy agreed moderately both between the independent coders as well as with the hospital assigned cause of death using the Kappa statistics for agreement beyond chance. We therefore concluded that verbal autopsies appear moderately useful for adult death statistics (Kappa = 0.23 to 0.1). Accumulation of more hospital deaths is needed, however, to make more definite conclusions about the validity of the technique.

Adolescent↗
PubMed1999

The distribution and mortality impact of chronic energy deficiency among adult Nigerian men and women.

OBJECTIVE: To determine the prevalence of chronic energy deficiency (CED) and associated mortality risk in a cohort of adult Nigerians followed from 1992 to 1997. RESEARCH METHODS AND PROCEDURES: The data for this investigation were derived from an international collaborative study on chronic diseases in populations of the African diaspora. Body mass index (BMI) was used to define three grades of CED in 4061 men and women aged 25 years and older: Grade I (mild CED) as BMI 17.5-18.4, Grade II (moderate CED) as BMI 16.0-17.4, and Grade III (severe CED) as BMI < 16.0 and BMI > or = 18.5 was considered normal. The odds of mortality associated with differing grades of CED was estimated with logistic regression analysis. RESULTS: The prevalence of CED (BMI < 18.5) increased from 14.3% in 1992 to 19.6% in 1997, both genders combined. The prevalence of CED was similar for both sexes in 1992 (14%) but increased to 22.4% in men and 17.4% in women by 1997. The prevalence of CED was 8.5%, 7.6 and 3.4 for Grades I, II and III, respectively. Two hundred and seven deaths occurred during the follow-up period. The mortality rate for the 5.5 y of follow-up was 5.1% (207/4061). The odds ratios (95% CIs) for all cause mortality were 1.4 (0.5, 3.8), 2.4 (1.2, 4.9) and 2.5 (1.0, 6.2), respectively, for CED grades I, II and III adjusting for age and sex. CONCLUSION: Under nutrition is an increasing problem in Nigerian men and women. The economic reforms (structural adjustment program (SAP)) introduced in 1986 in combination with the continued economic woes brought on by political instability, corruption and nepotism have been advanced by several investigators as the main factors in the growing problem of inadequate calorie intake. Intervention strategies both at the government and private sectors are urgently needed to increase food availability.

Adult↗
PubMed1999

Diabetes in the Caribbean: results of a population survey from Spanish Town, Jamaica.

AIMS: To characterize the prevalence of diabetes and associated risk attributes in the Jamaican population. METHODS: A random population sample was recruited by door-to-door canvassing (n = 1303). A final participation of 60% was achieved. Oral glucose tolerance testing was conducted after an overnight fast and standard anthropometric and demographic data were collected. RESULTS: The prevalence of Type 2 diabetes mellitus was 9.8% (95% confidence interval (CI) 7.2-12.4) among men and 15.7% (95% CI 13.1-18.3) among women with an overall prevalence of 13.4% (95% CI 11.5-15.2). Impaired glucose tolerance was found among 12.3% of men and 14.7% of women. The sex patterns were consistent with a fourfold excess of obesity in women compared to men. The odds ratios for diabetes, fourth vs. first quartiles were 5.42 (95% CI 2.02-16.88) in men and 3.32 (95% CI 1.73-6.63) in women for body mass index (BMI) and 17.39 (95% CI 3.86-78.27) in men and 5.48 (95% CI 2.84-11.00) in women for WHR in a logistic model controlling for age. The population attributes risk percentage, for diabetes, of being overweight and having waist-to-hip ratio (WHR) greater than the median (0.80) were 66% and 80%, respectively. The contribution of central obesity, as characterized by WHR, was also significant in sex-specific multivariate models that included age and BMI. Prevalent hypertension and family history of diabetes were likewise associated with increased odds of having the disease. CONCLUSIONS: The prevalence of diabetes in Jamaica now exceeds that observed among European-origin populations and reflects the emerging epidemic of obesity. The excess risk for this population could not be attributed entirely to relative weight. The pronounced sexual dimorphism in diabetes prevalence most likely reflects the substantial excess of obesity among women compared to men. Like many other island nations, Caribbean societies now appear to be at substantial risk of diabetes.

Aged↗
PubMed1999

Evidence of a major gene effect for angiotensinogen among Nigerians.

To dissect the genetic pathway of hypertension, we measured angiotensinogen in 685 members of 186 families recruited from a rural community in southwest Nigeria. Commingling and segregation analyses were carried out. A mixture of two and/or three distributions fits the data significantly better than a single distribution in commingling analysis, suggesting a major gene effect. Segregation analysis confirmed that a recessive major gene model for low values of angiotensinogen provides the best fit to the data and about 13% of the variance was due to the recessive gene segregation.

Adolescent↗
PubMed1997

Hypertension, serum angiotensinogen, and molecular variants of the angiotensinogen gene among Nigerians.

BACKGROUND: We evaluated the association among the M235T and T174M variants of the angiotensinogen (AGT) gene, plasma AGT, and hypertension status in a sample of Nigerians. METHODS AND RESULTS: Participants were selected from the extremes of the blood pressure distribution obtained from the population survey of 2509 men and women aged 25 to 74 years. Cases (hypertensive subjects) were individuals who had high blood pressure or were taking antihypertensive medication, and control subjects were individuals with low blood pressure who had never taken antihypertensive medication. We found a significant association between the M235T variant and plasma AGT level. Hypertensive subjects had higher plasma AGT levels compared with control subjects. The allele frequencies of the two variants were similar in the hypertensive patients and the control subjects. CONCLUSIONS: The consistent relationships observed between the M235T variant and the protein product and between plasma level of the protein and hypertension status in different ethnic groups provide some evidence for a biochemical mechanism linking DNA variation in the renin-angiotensin system with the hypertension phenotype.

Adult↗
PubMed1997

Relation between body mass index and body fat in black population samples from Nigeria, Jamaica, and the United States.

Body mass index (BMI) is the most commonly used measure of obesity. Recently, some investigators have advocated direct measurement of adiposity rather than use of the BMI. This study was undertaken to determine the ability of BMI to predict body fat levels in three populations of West African heritage living in different environments. A total of 1,054 black men and women were examined in Nigeria, Jamaica, and the United States during 1994 and 1995. A standardized protocol was used to measure height, weight, waist and hip circumferences, and blood pressure at all sites; percentage of body fat was estimated using bioelectrical impedance analysis. Percentage of body fat and BMI were highly correlated within site- and sex-specific groups, and the resulting r2 ranged from 0.61 to 0.85. The relation was quadratic in all groups except Nigerian men, in whom it was linear. The regression coefficients were similar across sites, yet the mean body fat levels differed significantly (p < 0.001) as estimated by the intercept, making intersite comparison difficult. Compared with BMI, percentage of body fat was not a better predictor of blood pressure or waist or hip circumference.

Adult↗
PubMed1997

A case-control study of lung cancer at a foundry and two engine plants.

A nested case-control study of lung cancer was conducted among workers at an iron foundry and two engine manufacturing plants whose lung cancer mortality rates were slightly higher than expected. The study included 231 lung cancer cases and 408 controls for whom complete work histories were obtained. There was no association between usual plant of employment and lung cancer mortality. The odds ratio for persons employed for 20 or more years in the foundry compared with persons employed in the engine plants was 0.90 (95% confidence interval: 0.55, 1.5). Long-term employment as an engine plant worker was associated with odds ratios slightly, but not statistically significantly, below unity. In the foundry, only usual employment in the material handling departmental group and any employment in the quality control departmental group were statistically significantly directly related to lung cancer risk. However, the number of subjects so employed was small and there was no dose-response relation between length of employment in these departmental groups and lung cancer risk. Cases were less frequently employed than were controls in engine plant machining and assembly jobs and departments. It is concluded that employment in this facility was either unrelated, or only weakly related, to lung cancer risk.

Carcinogens↗
PubMed1997

Heritability of plasma leptin in a population sample of African-American families.

The aim of this study was to examine familial patterns of plasma leptin levels and the potential association with cardiovascular risk factors in a population sample of African-American families recruited from metropolitan Chicago. The study included 68 mothers, 31 fathers, 143 daughters, and 119 sons, for a total of 361 individuals from 118 families. Leptin levels were adjusted for the effect of age separately for mothers, fathers, daughters, and sons. Residuals were then standardized before estimating familial correlation using the maximum-likelihood method available in SEGPATH. With the exception of height, plasma leptin level was strongly correlated with all measured anthropometric variables. Familial effect (i.e., heritability) of leptin levels was estimated as 39% in this population at high risk for over weight. A significant sex difference was observed, and most of the estimated familial effect may be attributed to genetic influences since the spouse correlation was not statistically different from zero. A strong nonshared environmental effect is also suggested, however.

Anthropometry↗
PubMed1997

The angiotensin converting enzyme and blood pressure in Jamaicans.

An insertion/deletion (I/D) polymorphism of the angiotensin I converting enzyme gene influences the level of serum angiotensin converting enzyme activity and has been associated with risk of several cardiovascular conditions. The relationship to blood pressure remains uncertain, however. We conducted a population-based survey in Kingston, Jamaica, to examine the association between angiotensin converting enzyme genotype, angiotensin converting enzyme serum activity and blood pressure. Serum angiotensin converting enzyme activity was measured and genotyping performed for the I/D polymorphism in 500 community residents. The overall prevalence of the D allele was 59.3%. Angiotensin converting enzyme genotype was not significantly related to blood pressure (P = .16), although it did influence angiotensin-converting enzyme activity, leading to an increase of 35% among individuals with the DD as compared with II genotype. Angiotensin converting enzyme levels were significantly higher in hypertensives as compared with normotensives (P < .05). A modest correlation was observed between blood pressure and angiotensin converting enzyme activity among untreated individuals (r = 0.11; P = .04), although this did not persist in multivariate analysis. A relationship between body mass index and angiotensin converting enzyme activity was identified in both men and women that was independent of genotype. These data demonstrate findings among blacks which are consistent with other studies and suggest a relationship between angiotensin converting enzyme genotype, and serum activity which is influenced by both genetic and environmental factors. The potential role of ACE on blood pressure control in the population remains uncertain.

Adult↗
PubMed1997

Hypertension in blacks.

The excess of hypertension among blacks has been recognized since early in this century and explains a substantial portion of the black health disadvantage. In a cohort study begun in the 1970s, hypertension accounted for 20% of all-cause mortality among blacks, compared to 10% among whites. National data on trends in hypertension (140/90 mm Hg or treatment) prevalence from 1960 to 1990 suggest a decline from 44% to 32%, although differences in survey technique likely account for this pattern. During this period the prevalence ratio of black:white remained constant at 1.5, suggesting that secular trends in causal factors, if any, effected both groups equally. Recent data demonstrate a gradient in risk across the African diaspora, with standardized prevalences of 14% in West Africa and 26% in the Caribbean, compared to 33% in the US. This pattern parallels the gradient in known risk factors, with obesity alone accounting for a third of the excess in the US compared to Africa. Why the black excess of hypertension in the US? Despite widespread speculation, unique characteristics of hypertension among blacks have yet to be established. Consistent evidence demonstrates a similar impact of the known risk factors in all population groups. Epidemiologic evidence likewise suggests that a similar risk of complications exists with blood pressure elevation among blacks and whites, level for level. Although the genetic epidemiology of hypertension is still in its infancy, no clear cross-population differences are yet apparent. Pathophysiologic traits that are known to be part of the causal etiologic pathway have not been shown to vary across groups. Unique features of this condition among blacks are likely to be restricted to the different mixes and intensities of risk factors. In the absence of evidence to support the hypothesis, it is perhaps surprising that credence continues to be given to the notion of black exceptionalism. Am J

Black People↗