Search PubMed⌕ Search

Biomedical subjects

S Preston-Martin

Publications and source records attributed to S Preston-Martin.

At least 37 records · Page 2Linked to original sources
PubMed1999

A pooled analysis of case-control studies of thyroid cancer. I. Methods.

OBJECTIVE: Because the etiology of thyroid cancer is not well described, we conducted a pooled analysis of all published case-control studies, as well as two identified unpublished studies. This paper describes the major characteristics of the 14 studies included in the analysis, as well as the statistical methods employed. Four studies were conducted in the United States (1 each in Washington State, California, Connecticut and Hawaii), 8 in Europe (3 in Sweden, 2 in Norway, 1 in Switzerland, 1 in Italy and 1 in Greece), and 2 in Asia (1 in China and 1 in Japan). METHODS: The original datasets were obtained and restructured in a uniform format. Data on socio-demographic characteristics, anthropometric measures, smoking and alcohol consumption, history of benign thyroid diseases and of other selected medical conditions and treatments, family history of cancer and of benign thyroid conditions, occupation, residence in endemic goitre areas, and dietary habits were analyzed. For women, we also analyzed menstrual and reproductive factors and use of female hormones. Radiotherapy and, in Japan, exposure to the A-bombs were considered as potential confounding factors. RESULTS: A total of 2,725 cases (2,247 females and 478 males) and 4,776 controls (3,699 females and 1,077 males) were included in this study. Of the cases, 79% were classified as papillary thyroid carcinomas, 14% as follicular, 2% medullary, 1% anaplastic, 1% other histologies, and 3% histological type unknown. Each of the datasets was checked for outliers and consistency. Data were analysed separately by study center, gender, and the two major histologic types (papillary, follicular). Frequency tables and simple statistics were computed for each variable under study. Conditional logistic regression was used to compute odds ratios. For matched studies, the original matching was preserved, whereas, for unmatched ones, five-year age groups were used for matching. Study-specific analyses were computed, and then the data from all the studies were pooled conditioning on study. Heterogeneity between studies, geographic areas and study designs was assessed, and the modifying effect of age was also evaluated.

Adenocarcinoma, Follicular↗
PubMed1999

A pooled analysis of case-control studies of thyroid cancer. II. Menstrual and reproductive factors.

OBJECTIVE: It has been suggested that female hormones, and hence menstrual and reproductive factors, play a role in thyroid cancer etiology. Epidemiological data, however, are limited and inconsistent, partly because of the small number of cases included in each study. To clarify the etiology of thyroid cancer, we conducted a pooled analysis of original data from 14 case-control studies, 4 from the United States, 2 from Asia, and 8 from Europe. METHODS: This analysis included a total of 2,247 female cases of thyroid cancer (80% papillary) and 3,699 control women. Pooled odds ratios (OR) were estimated using logistic regression, conditioning on study and (i) matching sets for individually matched studies, or (ii) quinquennia of age for the other studies. Additional terms for age and history of radiation exposure were included in the regression equations. RESULTS: The OR per year of later menarche was 1.04 (95% confidence interval (CI) 1.0-1.1). Compared to premenopausal women, the OR was 1.3 for women with natural menopause, and 1.8 for those with artificial menopause, but the studies were heterogeneous and the association may be due, at least in part, to diagnostic or ascertainment bias. Parity, spontaneous or induced abortions and history of infertility were not associated with thyroid cancer risk. The OR was above unity in women reporting later age at first birth (OR = 1.1, 95% CI 1.0-1.3 for 5-year delay) and higher in the first years after a birth. CONCLUSIONS: The associations of menstrual and reproductive factors with thyroid cancer risk were generally weak, but appeared stronger among women diagnosed with thyroid cancer at younger ages.

Adenocarcinoma, Papillary↗
PubMed1999

A pooled analysis of case-control studies of thyroid cancer. IV. Benign thyroid diseases.

OBJECTIVE: To obtain more precise estimates of the association between thyroid cancer and benign thyroid diseases and to elucidate the role of potential confounders or effect modifiers. METHODS: The original data from 12 case-control studies from the United States, Asia, and Europe were pooled. Based on 2,094 women and 425 men with cancer of the thyroid and, respectively, 3,248 and 928 control subjects, odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) were obtained by conditional regression models, conditioning on study and age at diagnosis, and adjusting for age and radiotherapy. RESULTS: A history of hypothyroidism was not associated with cancer risk (pooled ORs = 0.9, 95% confidence interval, CI: 0.7-1.3 in women and 1.7, 95% CI: 0.3-11.7 in men). ORs for hyperthyroidism were 1.4 (95% CI: 1.0-2.1) in women and 3.1 (95% CI: 1.0-9.8) in men. In women, however, risk was lower in the absence of or after allowance for history of goiter. Pooled ORs for a history of goiter were 5.9 (95% CI: 4.2-8.1) in women and 38.3 (95% CI: 5.0-291.2) in men. Risk for a history of benign nodules/adenomas was especially high (OR = 29.9, 95% CI: 14.5-62.0, in women; 18 cases versus 0 controls in men). The excess risk for goiter and benign nodules/adenomas was greatest within 2-4 years prior to thyroid cancer diagnosis, but an elevated OR was present 10 years or more before cancer. CONCLUSIONS: Goiter and benign nodules/adenomas are the strongest risk factors for thyroid cancer, apart from radiation in childhood.

Adenoma↗
PubMed1999

SEARCH international case-control study of childhood brain tumours: role of index pregnancy and birth, and mother's reproductive history.

A series of co-ordinated population-based case-control studies of childhood brain tumours (CBT) was undertaken under the auspices of the Surveillance of Environmental Aspects Related to Cancer in Humans (SEARCH) programme of the International Agency for Research on Cancer (IARC) to evaluate, inter alia, the risk in relation to characteristics of the index pregnancy and birth, and maternal reproductive history. Subjects comprised 1218 cases aged 0-19 years and 2223 controls. Risk estimates were calculated by unconditional logistic regression, adjusted for age, sex, centre and mother's years of schooling, for all types of CBT combined as well as for four groups defined by histopathology (astrologlial tumours, primitive neuroectodermal tumours of the brain, 'other glial' tumours and 'other histological types') and for five age groups (0-1, 0-4, 5-9, 10-14, 15-19 years). Use of anaesthetic 'gas' was associated with an increased risk of CBT (OR = 1.5, 95% CI [1.1, 2.0]), apparent in children aged 0-4 years (OR = 2.4, 95% CI [1.4, 4.1]) and for astroglial tumours (OR = 1.6, 95% CI [1.1, 2.2]) with non-significantly increased relative risks for each of the other histological groups. However, not all centre-specific relative risks were elevated. No other aspect of the index pregnancy, delivery and early neonatal period or of the mother's previous reproductive history was associated with risk for CBT.

Adolescent↗
PubMed1999

Foci of tuberculosis transmission in central Los Angeles.

To identify sites of tuberculosis transmission and to determine the contribution of HIV-infected patients to tuberculosis morbidity in an urban area, we prospectively evaluated 249 patients with culture-proven tuberculosis in central Los Angeles. Restriction fragment length polymorphism (RFLP) analysis was performed on Mycobacterium tuberculosis isolates to identify patients infected with the same strain. Using RFLP and clinical and epidemiologic data, we identified the most likely source case and site of transmission for 79 patients. Homelessness, birth in the United States and Native American ethnicity were independent predictors of being a source case, but HIV infection was not. Three homeless shelters were sites of tuberculosis transmission for 55 (70%) of the 79 patients. HIV-infected patients constituted 27% (66/249) of the study population, but only 17% (13/79) of patients were infected by an HIV-infected source case. We conclude that transmission of tuberculosis in central Los Angeles was highly focal, and that the major transmission sites were three homeless shelters. HIV- infected tuberculosis patients did not play a major role in spread of tuberculosis. Tuberculosis control measures targeted at specific homeless shelters can reduce tuberculosis morbidity in urban areas where homelessness is common and the incidence of tuberculosis is high.

AIDS-Related Opportunistic Infections↗
PubMed1999

Reproductive and hormonal risk factors for thyroid cancer in Los Angeles County females.

We conducted an individually matched case-control study (292 pairs) of female thyroid cancer patients to examine the role of reproductive history and exogenous hormones in this disease. Radiation treatment to the head or neck [28 cases and 2 controls exposed; odds ratio (OR), 14.0; 95% confidence interval (CI), 3.5-121.3] and certain benign thyroid diseases (including adolescent thyroid enlargement, goiter, and nodules or tumors) were strongly associated with thyroid cancer. Irregular menstruation increased risk (OR, 1.8; 95% CI, 0.9-3.7). Age at menarche and pregnancy history were not related to disease. Women with natural menopause and hysterectomized women without oophorectomy had no increase in risk, but disease risk was elevated in women with bilateral oophorectomy (OR, 6.5; 95% CI, 1.1-38.1). In general, use of oral contraceptives and other exogenous estrogens was not associated with thyroid cancer. However, risk increased with number of pregnancies in women using lactation suppressants (P = 0.03) and decreased with duration of breastfeeding (P = 0.04). These data provide only limited support for the hypothesis that reproductive and hormonal exposures are responsible for the marked excess of thyroid cancer risk in adult females.

Adenocarcinoma, Follicular↗
PubMed1998

Prenatal vitamin supplementation and pediatric brain tumors: huge international variation in use and possible reduction in risk.

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976-1994 and mothers of population controls. Data are available on maternal vitamin use during pregnancy for 1051 cases and for 1919 controls in eight geographic areas of North America, Europe and Israel. While risk estimates varied by study center, combined results suggest that maternal supplementation for two trimesters may decrease risk of brain tumor [odds ratio (OR)=0.7; 95% confidence interval (CI)=0.5-0.9], with a trend toward less risk with longer duration of use (P trend= 0.0007). The greatest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all three trimesters (OR=0.5; CI=0.3- 0.8). This effect did not vary by histology and was seen for supplementation during pregnancy rather than during the month before pregnancy or while breast feeding. These findings are largely driven by data from the US, where most mothers took vitamins. The proportion of control mothers who took vitamins during pregnancy varied tremendously, from 3% in Israel and in France through 21% in Italy, 33% in Canada, 52% in Spain to 86-92% at the three US centers. The composition of the various multivitamin compounds taken also varied: daily dose of vitamin C ranged from 0 up to 600 mg; vitamin E from 0 to 70 mg; vitamin A from 0 to 30,000 IU and folate from 0 to 2000 mg. Mothers also took individual micronutrient supplements (e.g., vitamin C tablets), but most mothers who took these also took multivitamins, making it impossible to determine potential independent effects of these micronutrients.

Adolescent↗
PubMed1998

Occupational exposure to magnetic fields and brain tumours in central Sweden.

Occupations with exposure to magnetic fields were studied in a population-based case-control study of male glioma and meningioma in Central Sweden. The study included 84 cases of glioma, 20 cases of meningioma and 155 controls. Information about job titles was obtained by means of a questionnaire. Three different methods were used to classify exposure 1) 'electrical occupations', 2) assessment of magnetic fields by an electrical engineer, 3) job values based on magnetic field measurements at work sites for occupational groups. When analyses were based on 'electrical occupations' a relative risk (RR) of 1.0 (95% CI: 0.4-2.4) was seen for glioma and 1.8 (95% CI: 0.3-3.6) for meningioma. When analyses were based on measurements a relative risk of 1.9 (95% CI: 0.8-5.0) was seen for glioma and 1.6 (95% CI: 0.3-10.2) for those ever in an exposed job of an average mean value of > 0.4 microT. A larger number of individuals was classified as exposed, when exposure was based on measurements. Information was available regarding several potential confounders, but none of them seemed to be of any importance. Our conclusion is that the results based on magnetic field measurements give some support to the hypothesis that magnetic fields exposure may play a role in the development of brain tumours.

Adult↗
PubMed1998

An international case-control study of adult glioma and meningioma: the role of head trauma.

BACKGROUND: Increased brain tumour risk after head trauma suggested by case reports and clinical series has been previously studied epidemiologically with mixed results. An international multicentre case-control study investigated the role of head trauma from injury or sports participation in adult brain tumour risk. METHODS: In all, 1178 glioma and 330 meningioma cases were individually or frequency matched to 2236 controls. Only exposures that occurred at least 5 years before diagnosis and head injuries that received medical attention were considered. RESULTS: Risk for ever having experienced a head injury was highest for male meningiomas (odds ratio [OR] = 1.5, 95% confidence interval [CI] : 0.9-2.6) but was lower for 'serious' injuries, i.e. those causing loss of consciousness, loss of memory or hospitalization (OR = 1.2, 95% CI: 0.6-2.3). Among male meningiomas, latency of 15 to 24 years significantly increased risk (OR = 5.4, 95% CI: 1.7-16.6), and risk was elevated among those who participated in sports most correlated with head injury (OR = 1.9, 95% CI: 0.7-5.3). Odds ratios were lower for male gliomas (OR = 1.2, 95% CI : 0.9-1.5 for any injury; OR = 1.1, 95% CI: 0.7-1.6 for serious injuries) and in females in general. CONCLUSIONS: Evidence for elevated brain tumour risk after head trauma was strongest for meningiomas in men. Findings related to sports should be interpreted cautiously due to cultural variability in our data and our lack of complete data on physical exercise in general which appeared to be protective.

Adult↗
PubMed1998

Parental occupation and childhood brain tumors: astroglial and primitive neuroectodermal tumors.

Data from a population-based case-control study in 19 counties in California and Washington State were used to investigate the association between parental employment and childhood brain tumors. Parents of 540 cases (including 308 astroglial and 109 primitive neuroectodermal tumors) and 801 controls diagnosed from 1984 to 1991 were interviewed. Analysis was completed for parents' self-reported industry of employment and job tasks during the five years preceding the birth of the child. Parents who worked in the chemical industry were at increased risk of having had children with astroglial tumors (fathers' odds ratio [OR] = 2.1; 95% confidence interval [CI], 1.1-3.9); mothers' OR = 3.3; 95% CI, 1.4-7.7), but no trend by duration of employment was seen for mothers. Children of fathers employed as electrical workers were at increased risk of developing brain tumors of any histologic type (OR = 2.3; 95% CI, 1.3-4.0).

Astrocytoma↗
PubMed1998

Results from an international case-control study of childhood brain tumors: the role of prenatal vitamin supplementation.

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976 to 1994 and mothers of population controls. Data are available on maternal vitamin use during pregnancy for 1051 cases and 1919 controls from eight geographic areas in North America, Europe, and Israel. Although risk estimates varied by study center, combined results suggest that maternal supplementation for two trimesters may decrease risk of brain tumor (odds ratio [OR] 0.7, 95% confidence interval [CI] 0.5-0.9), with a trend of less risk with longer duration of use (p trend = 0.0007). The greatest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all three trimesters (OR 0.5, CI 0.3-0.8). This effect did not vary by histology and was seen for supplementation during pregnancy rather than during the month before pregnancy or while breast feeding. These findings are largely driven by data from the United States, where most mothers took vitamins. The proportion of control mothers who took vitamins during pregnancy varied tremendously: from 3% in Israel and France, 21% in Italy, 33% in Canada, 52% in Spain and 86 to 92% at the three U.S. centers. The composition of the various multivitamin compounds taken also varied: the daily dose of vitamin C ranged from 0 to 600 mg, vitamin E ranged from 0 to 70 mg, vitamin A ranged from 0 to 30,000 IU, and folate ranged from 0 to 2000 micrograms. Mothers also took individual micronutrient supplements (e.g., vitamin C tablets), but most mothers who took these also took multivitamins, making it impossible to determine potential independent effects of these micronutrients.

Adolescent↗
PubMed1998

The descriptive epidemiology of craniopharyngioma.

OBJECT: In this report the authors describe the epidemiology of craniopharyngioma. METHODS: The incidence of craniopharyngioma in the United States was estimated from two population-based cancer registries that include brain tumors of benign and borderline malignancy: the Central Brain Tumor Registry of the United States (CBTRUS) and the Los Angeles county Cancer Surveillance Program. Information on additional pediatric tumors was available from the Greater Delaware Valley Pediatric Tumor Registry (GDVPTR). The overall incidence of craniopharyngioma was 0.13 per 100,000 person years and did not vary by gender or race. A bimodal distribution by age was noted with peak incidence rates in children (aged 5-14 years) and among older adults (aged 65-74 years in CBTRUS and 50-74 years in Los Angeles county). Survival information was available from GDVPTR and the National Cancer Data Base (NCDB), a hospital-based reporting system. In the NCDB, the 5-year survival rate was 80% and decreased with older age at diagnosis. Survival is higher among children and has improved in recent years. CONCLUSIONS: Craniopharyngioma is a rare brain tumor of uncertain behavior that occurs at a rate of 1.3 per million person years. Approximately 338 cases of this disease are expected to occur annually in the United States, with 96 occurring in children from 0 to 14 years of age.

Adolescent↗
PubMed1998

The Women's Interagency HIV Study. WIHS Collaborative Study Group.

The Women's Interagency HIV Study comprises the largest U.S. cohort to date of human immunodeficiency virus (HIV)-seropositive women (N = 2,058) with a comparison cohort of seronegative women (N = 568). The methodology, training, and quality assurance activities employed are described. The study population, enrolled between October 1994 and November 1995 through six clinical consortia throughout the United States (totaling 23 sites) represents a typically hard-to-reach study population. More than half of the women in each cohort were living below the federally defined levels of poverty. The women ranged in age from 16 to 73 years; approximately one-quarter self-identified as Latina or Hispanic, over one-half as African-American not of Hispanic origin, and less than 20% as white, non-Hispanic origin. Self-reporting of HIV exposure risk included injection drug use by 34% of the seropositive women and 28% of the seronegative women, heterosexual contact (42% vs 26%), transfusion risk (4% vs 3%) and no identified risk (20% vs 43%). Demographic and HIV exposure risk characteristics of the seropositive cohort were comparable with characteristics of nationally reported AIDS cases in U.S. women. This well characterized cohort of HIV-seropositive and high-risk seronegative women represents a rich opportunity for future studies of HIV disease progression and pathogenesis.

Adolescent↗
PubMed1998

Farm and animal exposures and pediatric brain tumors: results from the United States West Coast Childhood Brain Tumor Study.

Nineteen counties from San Francisco and Los Angeles, California and Seattle, Washington were the United States sites for a large population-based case-control study of childhood brain tumors (CBTs), sponsored by the National Cancer Institute. CBT patients who were < 20 years of age and were diagnosed between 1984 and 1991 were reported to each region's cancer registry. The 801 control subjects were obtained by random digit dial and were frequency-matched to the 540 CBT patients in San Francisco and Seattle (one patient to two controls) and in Los Angeles (one patient to one control). Data collected by in-person interview with subjects' mothers were analyzed to investigate an association between risk for CBTs and life on a farm, exposure to farm animals (dairy cattle, beef cattle, pigs, sheep/goats, poultry, and horses), and some cat and non-farm horse exposures. Elevated risks for CBTs were observed in association with mothers' exposure to pigs [odds ratio (OR) = 3.8, 95% confidence interval (CI) = 1.2-12] and horses (OR = 2.2, 95% CI = 1.0-4.8) on a farm during the index pregnancy. Children diagnosed with primitive neuroectodermal tumors showed elevated risks for CBTs with personal and maternal prenatal exposure to pigs (child, OR = 4.0, 95% CI = 1.2-13; mother, OR = 11.9, 95% CI = 2.8-51) and poultry (child, OR = 3.0, 95% CI = 1.1-8.0; mother, OR = 4.0, 95% CI = 1.2-14). No other animal exposures of children or mothers were found to be consistently related to CBTs. Children diagnosed with primitive neuroectodermal tumors who were on a farm for > 1 year and were first on a farm when they were < 6 months of age also had increased risk for CBTs (OR = 3.9, 95% CI = 1.2-13). A somewhat increased risk for CBTs was found for children of mothers who ever had worked on livestock farms compared with mothers who never had worked on a farm (OR = 7.4, 95% CI = 0.86-64, based on five case mothers and one control mother who worked on livestock farms during the 5 years preceding the birth of the index child). The associations are consistent with those of two previous studies in Norway (P. Kristensen et al., Int. J. Cancer, 65: 39-50, 1996) and the United States and Canada (G. R. Bunin et al., Cancer Epidemiol. Biomark. Prev., 3: 197-204, 1994) that investigated the role of farm-related exposures in the etiology of CBTs.

Adolescent↗
PubMed1998

Prenatal vitamin supplementation and risk of childhood brain tumors.

An international case-control study of primary pediatric brain tumors included interviews with mothers of cases diagnosed from 1976 to 1994 and mothers of population controls. Data are available on maternal vitamin use during pregnancy for 1,051 cases and for 1,919 controls from 8 geographic areas in North America, Europe and Israel. While risk estimates varied by study center, combined results suggest that maternal supplementation for 2 trimesters decreased risk of brain tumor [odds ratio (OR) = 0.7; 95% confidence interval (CI) = 0.5, 0.9], with a trend of less risk with longer duration of use (p trend = 0.0007). The greatest risk reduction was among children diagnosed under 5 years of age whose mothers used supplements during all 3 trimesters (OR = 0.5; CI = 0.3, 0.8). This effect did not vary by histology and was seen for supplementation during pregnancy rather than during the month before pregnancy or while breastfeeding. Our findings are largely driven by data from the United States, where most mothers took vitamins. The proportion of control mothers who took vitamins during pregnancy varied markedly from 3% in Israel and in France, 21% in Italy, 33% in Canada and 52% in Spain to 86-92% at the 3 U.S. centers. The composition of the various multivitamin compounds taken also varied: daily dose of vitamin C ranged from 0 to 600 mg; vitamin E from 0 to 70 mg; vitamin A from 0 to 30,000 IU; and folate from 0 to 2,000 micrograms. Mothers also took individual micronutrient supplements (e.g., vitamin C tablets), but most mothers who took these also took multivitamins, making it impossible to determine the potential independent effects of these micronutrients.

Adolescent↗
PubMed1997

The descriptive epidemiology of craniopharyngioma.

The incidence of craniopharyngioma in the United States was estimated from two population-based cancer registries that include brain tumors of benign and borderline malignancy: the Central Brain Tumor Registry of the United States (CBTRUS) and Los Angeles county. Information on additional pediatric tumors was available from the Greater Delaware Valley Pediatric Tumor Registry (GDVPTR). The overall incidence of craniopharyngioma was 0.13 per 100,000 person years and did not vary by gender or race. A bimodal distribution by age was noted with peak incidence rates in children (aged 5-14 years) and among older adults (aged 65-74 years in CBTRUS and 50-74 years in Los Angeles county). Survival information was available from GDVPTR and the National Cancer Data Base (NCDB), a hospital-based reporting system. In the NCDB, the 5-year survival rate was 80% and decreased with older age at diagnosis. Survival is higher among children and has improved in recent years. Approximately 338 cases of craniopharyngiomas are expected to occur annually in the United States, with 96 occurring in children from 0 to 14 years of age.

Journal Article↗
PubMed1997

Patterns of tuberculosis transmission in Central Los Angeles.

CONTEXT: Recent studies suggest that many tuberculosis cases in urban areas result from recent transmission. Delineation of the epidemiologic links between patients is important to optimize strategies to reduce tuberculosis transmission. OBJECTIVE: To identify epidemiologic links among recently infected urban patients with tuberculosis. DESIGN: Prospective evaluation of patients with tuberculosis. SETTING: Central Los Angeles, Calif. PATIENTS: A total of 162 patients who had culture-proven tuberculosis. INTERVENTIONS: Patients were prospectively interviewed to identify their contacts and whereabouts. The IS6110-based and pTBN12-based restriction fragment length polymorphism analyses were performed on Mycobacterium tuberculosis isolates. Patients whose isolates had identical or closely related restriction fragment length polymorphism patterns were considered a cluster. Unconditional logistic regression was used to identify independent predictors of clustering. MAIN OUTCOME MEASURES: Relationship of clinical and epidemiologic variables to clustering. RESULTS: A total of 96 (59%) of 162 patients were in 8 clusters. Only 2 of the 96 clustered patients named others in the cluster as contacts. The degree of homelessness was an independent predictor of clustering. Compared with nonclustered patients, patients in 6 clusters were significantly more likely to have spent time at 3 shelters and other locations when at least 1 patient in the cluster was contagious, and these locations were independent predictors of clustering. Among nonhomeless persons, clustered patients were significantly more likely than nonclustered patients to have used daytime services at 3 shelters. CONCLUSIONS: (1) Traditional contact investigation does not reliably identify patients infected with the same M tuberculosis strain, and (2) locations at which the homeless congregate are important sites of tuberculosis transmission for homeless and nonhomeless persons. Measures that reduce tuberculosis transmission should be based on locations rather than on personal contacts.

Adolescent↗