|  | | The Department of Biostatistics
Selected Recent Publications
| Researchers | Title | Publication | Abstract | | Islam T, Muntner P, Webber LS, Morisky DE, Krousel-Wood MA. | Cohort study of medication adherence in older adults (CoSMO): extended effects of Hurricane Katrina on medication adherence among older adults. | Am J Med Sci. 2008 Aug;336(2):105-10. | Background: Previous research indicates that many patients with hypertension ran out of medications and had difficulties getting refills immediately after Hurricane Katrina. The extended effect of Hurricane Katrina on antihypertensive medication adherence is not well characterized.
Methods: Data were analyzed for 2194 participants who completed the baseline survey for the Cohort Study of Medication Adherence among Older Adults between August 2006 and September 2007. Based on pre-Katrina zip codes, the study population was categorized into high- and low-affected areas. Low medication adherence was defined as a score less than 6 on the 8-item Morisky Medication Adherence Scale.
Results: Prevalence of low adherence was similar among participants living in high and low affected areas. Low medication adherence was similar for participants with greater than or less than 25% of the residence damaged by Hurricane Katrina and for participants with and without symptoms of post-traumatic stress disorder. In high affected areas, nonsignificant associations were present for those who had moved since the storm and those with a friend or immediate family member who had died in the month after the storm. These factors were not associated with low medication adherence in low affected areas. In both high- and low-affected areas, lower scores on the hurricane coping self-efficacy scale were associated with low medication adherence (P < 0.05).
Conclusions: The effect of Hurricane Katrina on patient adherence to antihypertensive medication was limited in the second year after the storm. Intrinsic patient factors, such as low coping self-efficacy, remain important factors associated with low adherence. | | Boris NW, Brown LA, Thurman TR, Rice JC, Snider LM, Ntaganira J, Nyirazinyoye LN. | Depressive symptoms in youth heads of household in Rwanda: correlates and implications for intervention. | Arch Pediatr Adolesc Med. 2008 Sep;162(9):836-43. | Objective: To examine the level of depressive symptoms and their predictors in youth from one region of Rwanda who function as heads of household (ie, those responsible for caring for other children) and care for younger orphans.
Design: Cross-sectional survey
Setting: Four adjoining districts in Gigonkoro, an impoverished rural province in southwestern Rwanda.
Participants: Trained interviewers met with the eldest member of each household (n = 539) in which a youth 24 years old or younger was caring for 1 child or more.
Main Exposure: Serving as a youth head of household.
Main Outcome Measures: Rates and severity of depressive symptoms using the Center for Epidemiologic Studies Depression scale; measures of grief, adult support, social marginalization, and sociodemographic factors using scales developed for this study.
Results: Of the 539 youth heads of household, 77% were subsistence farmers and only 7% had attended school for 6 years or more. Almost half (44%) reported eating only 1 meal a day in the last week, and 80% rated their health as fair or poor. The mean score on the Center for Epidemiologic Studies Depression scale was 24.4, exceeding the most conservative published cutoff score for adolescents. Multivariate analysis revealed that reports of depressive symptoms that exceeded the clinical cutoff were associated with having 3 basic household assets or fewer, such as a mattress and a spare set of clothes (odds ratio [OR], 1.69; 95% confidence interval [CI], 1.06-2.70), eating less than 1 meal per day (OR, 1.68; 95% CI, 1.09-2.60), reporting fair health (OR, 1.32; 95% CI, 0.76-2.29) or poor health (OR, 2.33; 95% CI, 1.17-4.64), endorsing high levels of grief (OR, 2.67; 95% CI, 1.73-4.13), having at least 1 parent die in the genocide as opposed to all other causes of parental death (OR, 1.83; 95% CI, 1.10-3.04), and not having a close friend (OR, 1.91; 95% CI, 1.17-3.12). There was an interaction between marginalization from the community and alcohol use; youth who were highly marginalized and did not drink alcohol were more than 3 times more likely to report symptoms of depression (OR, 3.07; 95% CI, 1.73-5.42). When models were constructed by grouping theoretically related variables into blocks and controlling for other blocks, the emotional status block of variables (grief and marginalization) accounted for the most variance in depressive symptoms.
Conclusions: Orphaned youth who head households in rural Rwanda face many challenges and report high rates of depressive symptoms. Interventions designed to go beyond improving food security and increasing household assets may be needed to reduce social isolation of youth heads of household. The effect of head-of-household depressive symptoms on other children living in youth-headed households is unknown. | | Kelly TN, Gu D, Chen J, Huang JF, Chen JC, Duan X, Wu X, Yau CL, Whelton PK, He J. | Hypertension subtype and risk of cardiovascular disease in Chinese adults. | Circulation. 2008 Oct 7;118(15):1558-66. Epub 2008 Sep 22. | Background: We examined the relationship between hypertension subtype and cardiovascular disease incidence and mortality in Chinese adults.
Methods and Results: We conducted a prospective cohort study in a nationally representative sample of 169 871 Chinese men and women aged >or=40 years. Data on systolic (SBP) and diastolic blood pressure (DBP) and other variables were obtained at a baseline examination in 1991 with the use of standard protocols. Follow-up evaluation was conducted in 1999-2000, with a response rate of 93.4%. Hypertension subtypes were defined as combined systolic and diastolic hypertension (SBP >or=140 and DBP >or=90 mm Hg), isolated systolic hypertension (SBP >or=140 and DBP <90 mm Hg), isolated diastolic hypertension (SBP <140 and DBP >or=90 mm Hg), and 2 categories of treated hypertension (SBP <140 and DBP <90 mm Hg or SBP >or=140 and/or DBP >or=90 mm Hg). After participants with missing BP values were excluded, 169 577 adults were included in the analyses. Compared with normotensives, relative risks (95% CIs) of cardiovascular disease incidence and mortality were 2.73 (2.60 to 2.86) and 2.53 (2.39 to 2.68) for combined systolic and diastolic hypertension, 1.78 (1.69 to 1.87) and 1.68 (1.58 to 1.78) for isolated systolic hypertension, 1.59 (1.43 to 1.76) and 1.45 (1.27 to 1.65) for isolated diastolic hypertension, 2.01 (1.64 to 2.48) and 1.61 (1.28 to 2.03) for treated hypertension with SBP <140 and DBP <90 mm Hg, and 3.37 (3.07 to 3.69) and 2.88 (2.60 to 3.19) for treated hypertension with SBP >or=140 and/or DBP >or=90 mm Hg, respectively, after adjustment for important covariables.
Conclusions: Our results indicate that all hypertension subtypes are associated with significantly increased risk of cardiovascular disease in Chinese adults. Primary prevention of hypertension should be a public health priority in the Chinese population. | | Farley TA, Meriwether RA, Baker ET, Rice JC, Webber LS. | Where do the children play? The influence of playground equipment on physical activity of children in free play. | J Phys Act Health. 2008 Mar;5(2):319-31. | Background
Promotion of physical activity in children depends on an understanding of how children use play equipment.
Methods
We conducted observations over 2 years of children in 2nd through 8th grades in a schoolyard with 5 distinct play areas with different amounts of play equipment.
Results
Children were more likely to play in areas with more installed play equipment, with densities of children in equipped areas 3.3 to 12.6 times higher than in an open grassy field. There were no significant differences by play area in the percent of children who were physically active at all, but children were more likely to be very active in areas with basketball goals and an installed play structure than in an open field.
Conclusions
Playground equipment appeared to have a strong influence on where children played and a moderate influence on levels of activity. To maximize physical activity in children, playgrounds should be designed with ample and diverse play equipment. | | Pfeiffer KA, Dowda M, Schmitz KH, Going S, Ward D, Pate RR, Neumark-Sztainer D, Sirard JR, Webber LS. | Contribution of light physical activity to total daily physical activity in adolescent girls: 937: May 30 2:45 PM - 3:00 PM. | Med Sci Sports Exerc 2008 May;40(5). | For abstract, see Medicine & Science in Sports & Exercise May 2008;40(5). | | Farley T, Meriwether R, Baker E, Watkins L, Johnson C, Webber L. | Safe play spaces to promote physical activity in inner-city children: results from a pilot study of an environmental intervention. | Am J Public Health Sept 2007; 97(9):1625-1631. | Objectives
We evaluated the effect of providing a safe play space on the physical activity level of inner-city schoolchildren.
Methods
In 1 of 2 matched neighborhoods, we opened a schoolyard and provided attendants to ensure children's safety. Over the next 2 years we directly observed the number of children and their physical activity levels in the school-yard, as well as in the surrounding intervention and comparison neighborhoods. We also surveyed children in the schools in the intervention and comparison neighborhoods regarding sedentary activities.
Results
After the schoolyard was opened, a mean of 71.4 children used it on weekdays and 25.8 used it on weekends during the school year. When observed, 66% of these children were physically active. The number of children who were outdoors and physically active was 84% higher in the intervention neighborhood than the comparison neighborhood. Survey results showed that children in the intervention school reported declines relative to the children in the comparison school in watching television, watching movies and DVDs, and playing video games on weekdays.
Conclusion
When children were provided with a safe play space, we observed a relative increase in their physical activity. Provision of safe play spaces holds promise as a simple replicable intervention. | | Dreisbach AW, Rice JC, Japa S, Newman JW, Sigel A, Gill RS, Hess AE, Cemo AC, Fonseca JP, Hammock BD, Lertora JL, Hamm L. | Salt loading increases urinary excretion of linoleic acid diols and triols in healthy human subjects. | Hypertension 2008;51(3):755-761.
| Increased dietary linoleic acid has been associated with reduced blood pressure in clinical and animal studies possibly mediated by prostaglandins. Urinary linoleate and prostaglandin metabolite excretion were investigated in subjects exposed to a salt-loading/salt-depletion regimen. Twelve healthy subjects were recruited from the New Orleans population (before Hurricaine Katrina) and admitted to the Tulane-Louisiana State University-Charity Hospital General Clinical Research Center after a 5-day outpatient lead-in phase on a 160-mmol sodium diet. On inpatient day 1, the subjects were maintained on the 160-mmol sodium diet, and a 24-hour urine specimen was collected. On day 2, the subjects received 2 L of IV normal saline over 4 hours and continued on a 160-mmol Na+ diet (total: 460 mmol of sodium). Two 12-hour urine collections were obtained. On day 3, the subjects received three 40-mg oral doses of furosemide, two 12-hour urine collections were obtained, and the subjects were given a 10-mmol sodium diet. Urinary oxidized lipids were measured by high-performance liquid chromatography-tandem quadrupole mass spectroscopy. The excretion of the urinary linoleate metabolites, dihydroxyoctadecamonoenoic acids, and trihydroxyoctadecamonoenoic acids increased significantly during intravenous salt loading as compared with day 1 and the salt-depleted periods. The urinary excretion of 6-keto- prostaglandin F1[alpha] was unaffected by salt loading but was dramatically increased 7- to 10-fold by salt depletion. Prostaglandin E2 excretion was positively correlated with sodium excretion. The salt-stimulated production of linoleic acid diols and triols may inhibit tubular sodium reabsorption, thereby assisting in the excretion of the sodium load. | | Manguno-Mire G, Sautter F, Lyons J, Myers L, Perry D, Sherman M, Glynn S, Sullivan G | Psychological distress and burden among female partners of combat veterans with PTSD | Journal of Nervous & Mental Disease. Feb 2007. 195(2):144-151 | Psychological distress among cohabitating female partners of combat veterans with posttraumatic stress disorder (PTSD) was examined in a cross-sectional study using a modified version of the Health Belief Model. A convenient sample of 89 cohabitating female partners of male veterans in outpatient PTSD treatment was interviewed by telephone using a structured interview. Partners endorsed high levels of psychological distress with elevations on clinical scales at or exceeding the 90th percentile. Severe levels of overall psychological distress, depression, and suicidal ideation were prevalent among partners. Multivariate analyses revealed that perceived threat, recent mental health treatment, and level of involvement with veterans predicted global partner psychological distress. Partner burden was predicted by partner self-efficacy, perceived threat, barriers to mental health treatment, and partner treatment engagement. These findings are compelling since they demonstrate that partners of veterans with combat-related PTSD experience significant levels of emotional distress that warrant clinical attention. Psychological distress and partner burden were each associated with a unique combination of predictors, suggesting that although these constructs are related, they have distinct correlates and potentially different implications within the family environment. Future research should examine these constructs separately using causal modeling analyses to identify modifiable targets for interventions to reduce psychological distress among partners of individuals with PTSD. | | Lang EK, Myers L, Slakey D, Rogers B, Brammer M, Regenstein F | Aminocaproic-acid seal to reduce or prevent bleeding after liver biopsy | J of the Louisiana State Medical Society. Jan-Feb 2007. 159(1):46-9 | This study investigates the efficacy of an aminocaproic-acid seal to prevent or reduce the risk of bleeding attendant to liver biopsies. The simple technique of occluding the biopsy tract by injecting 1-2 mL of aminocaproic acid, a fibrinolysis inhibitor, while withdrawing the biopsy sheath appears to reduce substantially the risk of delayed bleeding. The technique may be most useful if large core biopsy needles must be used to provide an adequate specimen. | | Farley TA, Mason K, Rice J, Habel JD, Scribner R, Cohen DA | The relationship between the neighbourhood environment and adverse birth outcomes | Paediatric and Perinatal Epidemiology. May 2006. 20(3):188-100 | Background
Intrauterine growth retardation and preterm birth are more frequent in African-American women and women of lower socio-economic status, but the reasons for these disparities are not fully understood. The physical and social environments in which these women live may contribute to these disparities.
Methods
We conducted a multilevel study to explore whether conditions of mothers' neighbourhood of residence contribute to adverse birth outcomes independent of individual-level determinants. We analysed data from 105 111 births in 1015 census tracts in Louisiana during 1997-98, merging it with data from other existing sources on neighbourhood socio-economic status, neighbourhood physical deterioration, and neighbourhood density of retail outlets selling tobacco, alcohol and foods. After controlling for individual-level sociodemographic factors, tract-level median household income was positively associated with both birth weight-for-gestational-age and gestational age at birth. Neighbourhood physical deterioration was associated with these birth outcomes in ecological analyses but only inconsistently associated with them after controlling for individual-level factors. Neither gestational age nor birth weight-for-gestational-age was associated with neighbourhood density of alcohol outlets, tobacco outlets, fast-food restaurants or grocery supermarkets.
Conclusions
We conclude that measures of neighbourhood economic conditions are associated with both fetal growth and the length of gestation independent of individual-level factors, but that readily available measures of neighbourhood retail outlets are not. Additional studies are needed to better understand the nature of environmental influence on birth outcomes. | | Submit publication to the webmaster. |
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