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Biomedical subjects

Richard D Semba

Publications and source records attributed to Richard D Semba.

At least 37 records · Page 2Linked to original sources
PubMed2005

Impact of anemia and cardiovascular disease on frailty status of community-dwelling older women: the Women's Health and Aging Studies I and II.

BACKGROUND: The physiological basis of the geriatric syndrome of frailty, a clinical state of increased vulnerability to adverse outcomes such as disability and mortality, remains to be better characterized. We examined the cross-sectional relationship between hemoglobin (Hb) and a recently-validated measure of frailty in community-dwelling older women, and whether this relationship was modified by cardiovascular disease (CVD) status. METHODS: Data were pooled from women 70-80 years old participating in the Women's Health and Aging Studies I and II (Baltimore, MD, 1992-1996) with known frailty status and Hb > or = 10 g/dL (n = 670). Logistic regression was used to model the relationship between frailty and Hb, adjusting for demographics, major chronic diseases, and physiologic and functional impairments. RESULTS: Prevalence of frailty was 14%. Frailty risk was highest at the lowest Hb levels, and lowest at mid-normal Hb levels (e.g., 13-14 g/dL). Mildly low and low-normal Hb concentrations were independently associated with frailty. Compared to an Hb concentration equal to 13.5 g/dL, the adjusted odds of being frail were 1.9 (95% confidence interval: 1.1-3.4) and 1.5 (95% confidence interval: 1.0-2.1) times higher for Hb concentrations equal to 11.5 g/dL and 12 g/dL, respectively. A statistically significant (p <.05) multiplicative interaction between Hb level and CVD status with respect to frailty risk was observed. CONCLUSION: In community-dwelling older women, mildly low and low-normal Hb levels were independently associated with increased frailty risk. This risk was synergistically modified by the presence of CVD. These results suggest that mild anemia, and even low-normal Hb levels are independent, potentially modifiable risk factors for frailty in community-dwelling older adults.

Aged↗
PubMed2005

Breast milk retinol concentrations are not associated with systemic inflammation among breast-feeding women in Malawi.

The acute phase response and inflammation are associated with lower plasma retinol concentrations, but their effect on breast milk retinol concentrations is unclear. We measured plasma retinol concentrations, acute phase proteins, and breast milk retinol concentrations in 237 breast-feeding women at 2 wk postpartum in Blantyre, Malawi; 16.5% of the women had plasma retinol < 0.70 micromol/L and 14.8% had breast milk retinol < 1.05 micromol/L. Among women with and without inflammation [alpha(1)-acid glycoprotein (AGP) > 1 g/L and/or C-reactive protein (CRP) > 5 mg/L], geometric mean (95% CI) plasma retinol was 0.89 (0.84, 0.94) and 1.05 (1.01, 1.17) mumol/L, respectively (P < 0.0001). Among women with and without inflammation, geometric mean (95% CI) breast milk retinol was 2.12 (1.89, 2.36) and 2.05 (1.75, 2.39) micromol/L, respectively (P = 0.74). In multiple linear regression models adjusting for age, parity, education, BMI, and days postpartum, plasma retinol concentrations were associated with plasma AGP and CRP concentrations (P < 0.0001 and P = 0.01, respectively), whereas breast milk retinol concentrations were unaffected by plasma AGP and CRP concentrations (P = 0.22 and P = 0.86, respectively). These findings suggest that breast milk retinol concentrations are not affected by systemic inflammation.

Adult↗
PubMed2005

They starved so that others be better fed: remembering Ancel Keys and the Minnesota experiment.

During World War II, 36 conscientious objectors participated in a study of human starvation conducted by Ancel Keys and his colleagues at the University of Minnesota. The Minnesota Starvation Experiment, as it was later known, was a grueling study meant to gain insight into the physical and psychologic effects of semistarvation and the problem of refeeding civilians who had been starved during the war. During the experiment, the participants were subjected to semistarvation in which most lost >25% of their weight, and many experienced anemia, fatigue, apathy, extreme weakness, irritability, neurological deficits, and lower extremity edema. In 2003-2004, 18 of the original 36 participants were still alive and were interviewed. Many came from the Historic Peace Churches (Mennonite, Brethren, and Quaker), and all expressed strong convictions about nonviolence and wanting to make a meaningful contribution during the war. Despite ethical issues about subjecting healthy humans to starvation, the men interviewed were unanimous in saying that they would do it all over again, even after knowing the suffering that they had experienced. After the experiment ended, many of the participants went on to rebuilding war-torn Europe, working in the ministries, diplomatic careers, and other activities related to nonviolence.

History, 20th Century↗
PubMed2005

Chronic cytomegalovirus infection and inflammation are associated with prevalent frailty in community-dwelling older women.

OBJECTIVES: To evaluate the association between asymptomatic chronic cytomegalovirus (CMV) infection and the frailty syndrome and to assess whether inflammation modifies this association. DESIGN: Cross-sectional analysis. SETTING: Women's Health and Aging Study I & II, Baltimore, Maryland. PARTICIPANTS: Seven hundred twenty-four community-dwelling women aged 70 to 79 with baseline measures of CMV, interleukin-6 (IL-6), and frailty status. MEASUREMENTS: CMV serology and IL-6 concentrations were measured using enzyme-linked immunosorbent assay. Frailty status was based on previously validated criteria: unintentional weight loss, weak grip strength, exhaustion, slow walking speed, and low level of activity. Frail women had three or more of the five components, prefrail women had one or two components, and women who were not frail had none of the components. Multinomial logistic regression adjusted for potential confounders. RESULTS: Eighty-seven percent of women were CMV seropositive, an indication of chronic infection. CMV was associated with prevalent frailty, adjusting for age, smoking history, elevated body mass index, diabetes mellitus, and congestive heart failure (CMV frail adjusted odds ratio (AOR)=3.2, P=.03; CMV prefrail AOR=1.5, P=.18). IL-6 interacted with CMV, significantly increasing the magnitude of this association (CMV positive and low IL-6 frail AOR=1.5, P=.53; CMV positive and high IL-6 frail AOR=20.3, P=.007; CMV positive and low IL-6 prefrail AOR=0.9, P=.73; CMV positive and high IL-6 prefrail AOR=5.5, P=.001). CONCLUSION: Chronic CMV infection is associated with prevalent frailty, a state with increased morbidity and mortality in older adults; inflammation enhances this effect. Further prospective studies are needed to establish a causal relationship between CMV, inflammation, and frailty.

Aged↗
PubMed2005

The association between obesity and the frailty syndrome in older women: the Women's Health and Aging Studies.

OBJECTIVES: To determine whether obesity is associated with the frailty phenotype and, if so, whether comorbid conditions or inflammatory markers explain this association. DESIGN: Cross-sectional analysis of baseline data from the Women's Health and Aging Studies I (1992) and II (1994), complementary population-based studies. SETTING: Twelve contiguous ZIP code areas in Baltimore, Maryland. PARTICIPANTS: Five hundred ninety-nine community-dwelling women aged 70 to 79 with a body mass index (BMI) greater than 18.5 kg/m(2). MEASUREMENTS: The dependent variables were the frailty syndrome, including prefrailty, defined as presence of one or two of five frailty indicators (weakness, slowness, weight loss, low physical activity, exhaustion), and frailty, defined as three or more indicators. Independent variables included BMI, categorized using World Health Organization criteria as normal (18.5 to <25 kg/m(2)), overweight (25 to <30 kg/m(2)), and obese (>/=30 kg/m(2)); chronic diseases; C-reactive protein; and serum carotenoids. RESULTS: Being overweight was significantly associated with prefrailty, and obesity was associated with prefrailty and frailty. In all frail women, regardless of BMI group, a similar pattern of three defining frailty indicators was found: slowness, weakness, and low activity (with the addition of weight loss in the normal weight group.) In multinomial regression models, obesity was significantly associated with prefrailty (odds ratio (OR)=2.23, 95% confidence interval (CI)=1.29-3.84) and frailty (OR=3.52, 95% CI=1.34-9.13), even when controlling for covariates. CONCLUSION: Obesity is associated with the frailty syndrome in older women in cross-sectional data. This association remains significant even when multiple conditions associated with frailty are considered. Prospective studies are needed to confirm this finding.

Activities of Daily Living↗
PubMed2005

Status of carotenoids, vitamin A, and vitamin E in the mother-infant dyad and anthropometric status of infants in Malawi.

This prospective study was carried out during February 2000-April 2003 to characterize the relationship between the status of carotenoids, vitamin E, and retinol and anthropometric status in apparently healthy infants and their mothers in Blantyre, Malawi. Anthropometric status of infants and concentrations of carotenoids (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene), retinol, and alpha-tocopherol in plasma were measured in 173 infants at 12 months of age, and concentrations of carotenoids, retinol, and a-tocopherol in plasma were measured in their mothers two weeks postpartum. In multivariate analyses, concentrations of retinol, total carotenoids, non-provitamin A carotenoids, and alpha-tocopherol in infants were associated with under-weight (p = 0.05). Concentrations of a-tocopherol were associated with wasting (p = 0.04). Concentrations in mothers and infants were all correlated (correlation coefficients from 0.230 to 0.502, p < 0.003). The findings suggest that poor status of carotenoids, retinol, and alpha-tocopherol in infants is associated with their poor anthropometric status, and status of carotenoids, retinol, and alpha-tocopherol in mothers and infants has a low-to-moderate association in the mother-infant dyad.

Adult↗
PubMed2004

Micronutrient malnutrition and wasting in adults with pulmonary tuberculosis with and without HIV co-infection in Malawi.

BACKGROUND: Wasting and micronutrient malnutrition have not been well characterized in adults with pulmonary tuberculosis. We hypothesized that micronutrient malnutrition is associated with wasting and higher plasma human immunodeficiency virus (HIV) load in adults with pulmonary tuberculosis. METHODS: In a cross-sectional study involving 579 HIV-positive and 222 HIV-negative adults with pulmonary tuberculosis in Zomba, Malawi, anthropometry, plasma HIV load and plasma micronutrient concentrations (retinol, alpha-tocopherol, carotenoids, zinc, and selenium) were measured. The risk of micronutrient deficiencies was examined at different severity levels of wasting. RESULTS: Body mass index (BMI), plasma retinol, carotenoid and selenium concentrations significantly decreased by increasing tertile of plasma HIV load. There were no significant differences in plasma micronutrient concentrations between HIV-negative individuals and HIV-positive individuals who were in the lowest tertile of plasma HIV load. Plasma vitamin A concentrations <0.70 micromol/L occurred in 61%, and zinc and selenium deficiency occurred in 85% and 87% respectively. Wasting, defined as BMI<18.5 was present in 59% of study participants and was independently associated with a higher risk of low carotenoids, and vitamin A and selenium deficiency. Severe wasting, defined as BMI<16.0 showed the strongest associations with deficiencies in vitamin A, selenium and plasma carotenoids. CONCLUSIONS: These data demonstrate that wasting and higher HIV load in pulmonary tuberculosis are associated with micronutrient malnutrition.

AIDS-Related Opportunistic Infections↗
PubMed2004

Vitamin A deficiency and inflammatory markers among preschool children in the Republic of the Marshall Islands.

BACKGROUND: The exclusion of individuals with elevated acute phase proteins has been advocated in order to improve prevalence estimates of vitamin A deficiency in surveys, but it is unclear whether this will lead to sampling bias. The purpose of the study was to determine whether the exclusion of individuals with elevated acute phase proteins is associated with sampling bias and to characterize inflammation in children with night blindness. METHODS: In a survey in the Republic of the Marshall Islands involving 281 children, aged 1-5 years, serum retinol, C-reactive protein (CRP), and alpha1-acid glycoprotein (AGP) were measured. RESULTS: Of 281 children, 24 (8.5%) had night blindness and 165 (58.7%) had serum retinol < 0.70 micromol/L. Of 248 children with AGP and CRP measurements, 123 (49.6%) had elevated acute phase proteins (CRP > mg/L and/or AGP > 1000 mg/L). Among children with and without night blindness, the proportion with serum retinol < 0.70 micromol/L was 79.2% and 56.8% (P = 0.03) and with anemia was 58.3% and 35.7% (P = 0.029), respectively. The proportion of children with serum retinol < 0.70 micromol/L was 52.0% after excluding children with elevated acute phase proteins. Among children with and without elevated acute phase proteins, mean age was 2.8 vs 3.2 years (P = 0.016), the proportion of boys was 43.1% vs. 54.3% (P = 0.075), with no hospitalizations in the last year was 11.0% vs 23.6% (P = 0.024), and with anemia was 43.8% vs 31.7% (P = 0.05), respectively. CONCLUSIONS: Exclusion of children with inflammation in this survey of vitamin A deficiency does not improve prevalence estimates for vitamin A deficiency and instead leads to sampling bias for variables such as age, gender, anemia, and hospitalization history.

Journal Article↗
PubMed2004

Interactions between iron deficiency and lead poisoning: epidemiology and pathogenesis.

Iron deficiency and lead poisoning are common among infants and children in many parts of the world, and often these two problems are associated. Both conditions are known to cause anemia and appear to produce a more severe form of anemia when in combination. Although the nature of their relationship is not completely elucidated, characterization of a common iron-lead transporter and epidemiological studies among children strongly suggest that iron deficiency may increase susceptibility to lead poisoning. Recent human studies suggest that high iron intake and sufficient iron stores may reduce the risk of lead poisoning. Future clinical trials are necessary to assess the effect of iron supplementation in the public health prevention of lead poisoning and the kinetics of lead in the body.

Anemia, Iron-Deficiency↗
PubMed2004

Risk factors for xerophthalmia among mothers and their children and for mother-child pairs with xerophthalmia in Cambodia.

OBJECTIVE: To characterize the risk of xerophthalmia among nonpregnant women and their children and the risk factors for households in which both mother and child have xerophthalmia. METHODS: In case-control analyses of more than 15 000 households in the National Micronutrient Survey of Cambodia, univariate and multivariate logistic regression were used to estimate odds ratios (ORs) for nonpregnant mothers, children, and mother-child pairs with xerophthalmia. MAIN OUTCOME MEASURES: Risk factors for xerophthalmia. RESULTS: Of 10 942 children aged 18 to 60 months and 9587 nonpregnant women, the adjusted prevalence of xerophthalmia was 0.7% and 1.9%, respectively. In multivariate analyses, a child was at higher risk of xerophthalmia when the mother had xerophthalmia (OR = 4.36; 95% confidence interval [CI], 2.25-8.46), and a mother was at higher risk of xerophthalmia when a child had the disease (OR = 9.21; 95% CI, 3.56-23.82). Households were at higher risk for having both mother and child with xerophthalmia if there was a history of diarrhea in the mother (OR = 6.48; 95% CI, 1.49-28.23) or in a child younger than 60 months (OR = 10.16; 95% CI, 1.55-66.62) in the last 2 weeks. CONCLUSIONS: Xerophthalmia clusters among mothers and children in Cambodia and is associated with diarrheal disease. Interventions are needed to address vitamin A deficiency and diarrheal disease at the household level.

Adult↗
PubMed2004

Iron status and anemia in a population-based study of women with and without disability living in the community: the Women's Health and Aging Studies.

Iron status and associated risk factors were assessed in a population-based study of 684 community-dwelling women, 70-79 years old. Iron deficiency, iron deficiency anemia, and elevated iron stores were found in 5.8%, 3.8%, and 9.0% of women, respectively. The prevalence of both anemia and iron deficiency anemia increased significantly with increasing disability.

Aged↗
PubMed2004

Carotenoid status among preschool children with vitamin A deficiency in the Republic of the Marshall Islands.

Although carotenoids are known to be important dietary sources of vitamin A, there have been few epidemiological studies that have characterized the serum concentrations of major dietary carotenoids among preschool children with vitamin A deficiency. We conducted a population-based, cross-sectional study of serum pro-vitamin A carotenoids (alpha -carotene, beta-carotene, beta-cryptoxanthin), non-provitamin A carotenoids (lutein/zeaxanthin, and lycopene), and retinol among 278 children, aged 1-5 y, in the Republic of the Marshall Islands. Vitamin A deficiency was defined as serum retinol <0.70 micromol/L. Geometric mean serum concentrations of carotenoids among children with and without vitamin A deficiency were 0.003 vs 0.006 micromol/L for alpha-carotene (P = 0.0017), 0.011 vs 0.023 micromol/L for beta-carotene (P <0.0001), 0.023 vs 0.034 micromol/L for beta-cryptoxanthin (P = 0.0075), 0.007 vs 0.012 micromol/L for lycopene (P = 0.037), 0.044 vs 0.052 micromol/L for lutein/zeaxanthin (P = 0.2), and 0.045 vs 0.074 micromol/L for total provitamin A carotenoids (P <0.0001) respectively. In a multivariate analysis adjusting for sex, age (Odds Ratio [O.R.] 1.44, 95% confidence interval [C.I.] 1.16-1.78), and serum provitamin A carotenoids (O.R. 0.49, 95% C.I. 0.34-0.71) were associated with vitamin A deficiency, but serum non-provitamin A carotenoids were not associated with vitamin A deficiency (O.R. 0.93, 95% C.I. 0.67-1.28). Preschool children with vitamin A deficiency in the Republic of the Marshall Islands have extremely low serum concentrations of provitamin A carotenoids and interventions are needed to improve the dietary intake of provitamin A carotenoids among Marshallese children.

Antioxidants↗
PubMed2003

The ocular complications of smallpox and smallpox immunization.

Although smallpox was eradicated worldwide, concerns have been raised about the use of smallpox as a biological weapon. Plans are being considered for smallpox immunization in the United States. Variola virus, the cause of smallpox, and vaccinia virus, used in smallpox immunization, are both orthopoxviruses that are associated with serious ocular complications, including eyelid and conjunctival infection, corneal ulceration, disciform keratitis, iritis, optic neuritis, and blindness. About 5% to 9% of patients with smallpox develop ocular complications, and case-fatality rates reach 20% to 35% among unvaccinated individuals. About 10 to 20 patients develop ocular complications per 1 million smallpox immunizations, usually through autoinoculation, in which the patient transfers vaccinia from the immunization site to the eye. The risk of ocular vaccinia infection may be reduced by instructing patients and individuals in close contact with the vaccinee to wash their hands often and avoid touching the immunization site and their eyes. Topical antiviral therapy, topical steroids, and topical and oral antibiotics have been used to reduce the ocular complications of smallpox immunization. In contrast, there has been little experience with the use of these therapies for the ocular complications of smallpox.

Biological Warfare↗
PubMed2003

Carotenoid and vitamin E status are associated with indicators of sarcopenia among older women living in the community.

BACKGROUND AND AIMS: Oxidative stress may play a role in the pathogenesis of sarcopenia, and the relationship between dietary antioxidants and sarcopenia needs further elucidation. The aim was to determine whether dietary carotenoids and alpha-tocopherol are associated with sarcopenia, as indicated by low grip, hip, and knee strength. METHODS: Cross-sectional analyses were conducted on 669 non-disabled to severely disabled community-dwelling women aged 70 to 79 who participated in the Women's Health and Aging Studies. Plasma carotenoids and alpha-tocopherol were measured. Grip, hip, and knee strength were measured, and low strength was defined as the lowest tertile of each strength measure. RESULTS: Higher plasma concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, and lutein/zeaxanthin were associated with reduced risk of low grip, hip, and knee strength. After adjusting for potential confounding factors such as age, race, smoking, cardiovascular disease, arthritis, and plasma interleukin-6 concentrations, there was an independent association for women in the highest compared with the lowest quartile of total carotenoids with low grip strength [Odds Ratios (OR) 0.34, 95% Confidence Interval (CI) 0.20-0.59], low hip strength (OR 0.28, 95% CI 0.16-0.48), and low knee strength (OR 0.45, 95% CI 0.27-0.75), and there was an independent association for women in the highest compared with the lowest quartile of alpha-tocopherol with low grip strength (OR 0.44, 95% CI 0.24-0.78) and low knee strength (OR 0.52, 95% CI 0.29-0.95). CONCLUSIONS: Higher carotenoid and alpha-tocopherol status were independently associated with higher strength measures. These data support the hypothesis that oxidative stress is associated with sarcopenia in older adults, but further longitudinal and interventional studies are needed to establish causality.

Aged↗
PubMed2003

Vitamin A deficiency, iron deficiency, and anemia among preschool children in the Republic of the Marshall Islands.

OBJECTIVE: We investigated the co-occurrence of vitamin A deficiency, iron deficiency, and anemia among young children in the Republic of the Marshall Islands. METHODS: Hemoglobin, serum retinol, and serum ferritin were assessed in the Republic of the Marshall Islands Vitamin A Deficiency Study, a community-based survey that involved 919 children ages 1 to 5 y. RESULTS: The proportion of children with vitamin A deficiency (serum retinol concentrations < 0.70 microM/L) was 59.9%. The prevalences of anemia (hemoglobin < 110 g/L), iron deficiency (serum ferritin < 12 microg/L), and iron deficiency anemia (iron deficiency and anemia) were 36.4%, 53.5%, and 23.8%, respectively. The proportion of children who had co-occurrence of vitamin A and iron deficiencies was 33.2%. The mean ages of children with and without vitamin A deficiency were 3.2 +/- 1.4 and 2.9 +/- 1.5 y, respectively (P = 0.01), and the mean ages of those with and without iron deficiency were 2.7 +/- 1.3 and 3.5 +/- 1.4 y, respectively (P < 0.0001). CONCLUSIONS: Children in the Republic of the Marshall Islands, ages 1 to 5 y, are at high risk of anemia, vitamin A deficiency, and iron deficiency, and one-third of these children had the co-occurrence of vitamin A and iron deficiencies. Further investigation is needed to identify risk factors and evaluate interventions to address vitamin A and iron deficiencies among children.

Anemia↗
PubMed2003

Iron-deficiency anemia and the cycle of poverty among human immunodeficiency virus-infected women in the inner city.

The prevalence of iron-deficiency anemia appears to be extremely high among female injection drug users in the inner city who have human immunodeficiency virus (HIV) and/or hepatitis C (HCV) infections. Iron deficiency and its associated anemia may contribute to reduced energetic efficiency, lower aerobic capacity, decreased endurance, and fatigue. In practical terms, the functional limitations of iron deficiency and iron-deficiency anemia may affect the ability of women to participate in work, school, social, and family activities. Iron deficiency may contribute to the cycle of poverty in the inner city by limiting the ability of women to work, earn money, and afford iron-rich sources of food. Although iron supplementation may prevent or treat iron deficiency, the use of iron supplements needs to be approached with caution in women with HIV and HCV infections.

Anemia, Iron-Deficiency↗
PubMed2003

Triple trouble: the role of malnutrition in tuberculosis and human immunodeficiency virus co-infection.

Worldwide, the number of individuals who are co-infected with human immunodeficiency virus (HIV) and tuberculosis is increasing greatly. The "triple trouble" of HIV and tuberculosis infection and malnutrition may put those infected at greater risk than those with any of the three conditions alone. Further investigation is needed to evaluate the prophylactic and therapeutic potential of nutritional interventions for co-infection with HIV and tuberculosis.

Dietary Supplements↗