Pulse blood pressure and cardiovascular mortality in a population-based cohort of elderly Costa Ricans.

UNLABELLED: We studied the relationships between blood pressure (BP), pulse pressure (PP) and cardiovascular (CV) death in older adults using data from 2346 participants enrolled in the Costa Rican CRELES study, mean age 76 years (s.d. 10.2), 31% qualified as wide PP. All covariates included and analyzed were collected prospectively as part of a 4-year home-based follow-up; mortality was tracked for an additional 3 years, identifying 266 CV deaths. Longitudinal data revealed little change over time in systolic BP (SBP), a decline in diastolic BP, and widening of PP. Wide PP was associated with higher risk of CV death but only among individuals receiving antihypertensive drug therapy. Individuals with both wide PP and receiving therapy had 2.6 hazard rate of CV death relative to people with normal-PP plus not taking treatment (TRT), even adjusting for SBP. Increasing PP between visits was significantly associated to higher CV death independently of TRT status. SBP and DBP were not significantly associated to CV death when the effect of PP was controlled for. CONCLUSION: elderly hypertensive patients with wide or increasing PP, especially if receiving TRT, are the highest CV risk group, thus must be carefully assessed, monitored and treated with caution.

X-ray screening seems to reduce gastric cancer mortality by half in a community-controlled trial in Costa Rica.

X-ray screening of gastric cancer is broadly used in Japan, although no controlled trial has proved its effectiveness. This study evaluates the impact of an X-ray screening demonstrative intervention to reduce gastric cancer mortality in a Costa Rican region. The evaluation follows a quasi-experimental, community-controlled design, with measures before and after. About 7000 individuals participated by invitation in the two-wave screening programme. X-ray screening was followed by videoendoscopy and gastric biopsies. Treatment included resection with or without lymph node dissection. Comparisons with two control groups estimate that gastric cancer mortality was halved in the period from 2 to 7 years after the first screening visit. Validity of X-rays as used in this intervention had 88% sensitivity, 80% specificity, and 3% predictive value for individuals with two screening visits. Incidence in the screened group increased up to four times. Case survival was 85% in the intervention group after 5 years, compared to 12% among the controls before the intervention and 35% among the controls in the same region after the intervention. Although X-ray mass screening seems able to reduce stomach cancer mortality, its high cost may be an obstacle for scaling up this intervention in a non-rich country like Costa Rica.

Assessing and interpreting birth spacing goals in Costa Rica.

A procedure for assessing birth spacing goals, an important component of fertility preferences, is proposed and applied to 1993 Costa Rican data. Based on a reverse or backward survival analysis, preferred birth intervals are estimated to range between 3.5 and 4.5 years (1.5 years for the interval union to first birth). These intervals are 2 or 3 years shorter than crude estimates from data on open or last closed intervals, which are upwardly biased by selection and left censoring effects. To achieve these spacing preferences, a cohort must spend about two-thirds of the time using contraception (one-third in the interval union to first birth). An inverse association between desired family size and desired birth interval is evident only in parity-specific analyses.

PIP: Couples may use contraception in order to stop childbearing once they have borne their desired number of children and/or to lengthen birth intervals. A procedure for assessing birth spacing goals is proposed and applied to data collected in the 1992-93 Costa Rican Reproductive Health Survey (ESR). The ESR is a nationally representative, Demographic and Health Survey-type survey of approximately 3600 women aged 15-49 years. Based upon backward survival analysis, preferred birth intervals are estimated to range between 3.5 and 4.5 years, 2-3 years shorter than crude estimates of intervals using data on open or last closed intervals, which are upwardly biased by selection and left censoring effects. To achieve these spacing preferences, couples must spend about 40% of their time using contraception. An inverse relationship was identified between desired family size and desired birth interval in only parity-specific analyses.

Sexual behavior, sexually transmitted diseases, and risk of cervical cancer.

To explore sexually transmitted diseases and sexual behavior as risk factors for cervical cancer, we analyzed data from a population-based case-control study of breast and cervical cancer in Costa Rica. Data from 415 cases of cervical carcinoma in situ, 149 cases of invasive cervical cancer, and 764 controls were included in the analysis. Multivariate analysis showed that lifetime number of sex partners, first intercourse before age 15 years, number of livebirths, herpes simplex virus type 2 seropositivity, and serologic evidence of previous chlamydial infection were predictors of carcinoma in situ. Serologic evidence of previous syphilis was not associated with carcinoma in situ. Predictors for invasive cervical cancer included lifetime number of sex partners, first intercourse before age 15 years, number of livebirths, serologic evidence of previous syphilis, herpes simplex type 2 infection, and chlamydial infection. Cigarette smoking, socioeconomic status, self-reported history of sexually transmitted diseases, and douching were not associated with either carcinoma in situ or invasive cervical cancer.

[Diffusion through social interaction and fertility transition: quantitative and qualitative evidence from Costa Rica]. / Difusion por interaccion social y transicion de la fecundidad: evidencia cuantitativa y cualitativa de Costa Rica.

PIP: Explanations of the fertility transition in Costa Rica, as elsewhere in developing societies, have stressed the impacts of socioeconomic changes on the demand for children and of increased supply of family planning services. This paper goes beyond this demand-supply paradigm and examines the additional causal contribution of the "contagion" of birth control practices by social interaction. Aiming at conceptual precision, a simple dynamic model is used to simulate a fertility transition process with interaction diffusion effects. An inspection of the data about the Costa Rican transition shows several characteristics suggesting interaction diffusion effects, notably its pervasiveness toward all socioeconomic strata and the lack of evidence of a downward shift in fertility preferences. Maps of the timing of fertility transition indicate an ordered spatial pattern suggestive of contagion between neighboring areas. An areal regression analysis reveals inter- and within-area contagion effects on birth control adoption. Focus group discussions show real-life situations of interaction diffusion for birth control adoption. These discussions also give qualitative hints of the circumstances surrounding diffusion of birth control, as well as give hints of major value changes that paralleled fertility transition in Costa Rica. (author's)^ieng

[Adult mortality decline in Costa Rica]. / La disminucion de la mortalidad de adultos en Costa Rica.

"This paper examines the adult-mortality transition in Costa Rica and its determinants. The risk of dying declined by 80% for young adults and by 40% for old adults from 1920 to 1990. The fastest decline took place in the 1950s for young-adult ages and in the late 1980s for old-adult ages.... By 1990, about 40% of Costa Rican deaths are caused by accidents and violence at young-adult ages and by cardiovascular diseases at old ages. Infectious and nutritional-related conditions (especially respiratory tuberculosis and malaria) account for three-fourths of the adult-mortality decline between 1951 and 1971, but only for 30% since that year on." (SUMMARY IN ENG)

The effect of using different reference dates for control exposure measurement on relative risk estimates in a case-control study.

In case-control studies in which case and control enrollment periods are not identical, exposure status for time-dependent variables is often measured relative to a reference date. Using data from a case-control study of the relation between cervical cancer and oral contraceptive (OC) use in which control enrollment began 6 months after the end of case enrollment, we evaluated the effect on odds ratios from using five different reference dates to determine the controls' exposure status. The choice of reference date had little effect on the odds ratios in this study. Reference dates for time-dependent exposure variables should be considered carefully in studies when case and control enrollment periods are not identical.

[Nuptiality trends and the fertility transition in Latin America]. / Las tendencias de la nupcialidad y la transicion de la fecundidad en America Latina.

The author uses census data to examine the impact of nuptiality on the fertility transition in Latin America. He finds that fertility decreased among adolescents during the 1960s, although no trend was observed for later decades. However, "an increase of legal marriages in connection with consensual unions was also observed. Apart from an [increase] in the number of illegitimate children, the impact of the increase of consensual unions upon fertility is uncertain. No regional trend was observed in connection with age at marriage. This stability suggests that Latin American patterns of marriage are determined by cultural factors rather than socioeconomic reasons." (SUMMARY IN ENG)

A population-based serosurveillance of syphilis in Costa Rica.

As part of a case-control study to investigate the high incidence of cervical cancer in Costa Rican women, the seroprevalence of the treponematoses, in particular, syphilis was determined. In each age group, women with a history of two or more sex partners were two to four times more likely to be seroreactive in tests for syphilis than women with zero or one sex partner. The highest percentage of reactive results in the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP) was seen in samples from women aged 50-59 who had had two or more lifetime partners (23.8%). Three observations from our study support reactivity due to syphilis rather than yaws or pinta: (1) a similar percent of reactive rapid plasma reagin (RPR) card test results among MHA-TP reactors in the two age groups of women who were surveyed (42 vs. 49%) was observed; (2) women who were seroreactive in the MHA-TP had multiple risk factors for STD [low socioeconomic status (9.4%), urban residence (22.8%), first intercourse under 16 years of age (14.1%), and multiple sex partners (26.3%)], and (3) only sexually experienced women had reactive results in the MHA-TP test.

Socioeconomic development, health interventions and mortality decline in Costa Rica.

Costa Rica, whose life expectancy was 74 years by 1985, has reached a health level comparable to a developed country. The health achievements of this country are product of political and socioeconomic circumstances as well as of right public health policies. Until about 1970 the features of Costa Rica mortality, although somewhat better than the Latin American average, evolved in a similar way to the rest of the region. In particular, the decades of 1940s and 1950s saw dramatic improvements in life expectancy, thanks mainly to the import of low-cost, high-effectiveness health technologies. In the 1970s, however, Costa Rica departed from a regional pattern of stagnation and managed to close the gap with developed countries in terms of mortality levels. A dramatic decline in the infant mortality rate from 60 to 19 per 1,000 took place in this decade. The main determinants of this breakthrough were health interventions, notably a primary health care program, even though favorable socioeconomic conditions and a reduced fertility also played a role. Ecological data and other evidence suggest that up to three fourths of the mortality decline was accounted for contemporary improvements in public health services, with about 40 percent attributable to primary health care interventions. Furthermore, by targeting interventions on the less privileged population, these interventions had the merit of reducing geographic and socioeconomic differentials in child mortality.

PIP: This is an historical survey of the reasons for the rapid increase in life expectancy and decline in infant mortality in Costa Rica in this century, with regression analysis of determinants of infant mortality. Costa Rica, although a small, relatively poor Central American country, has as of 1985 a life expectancy of 74 years and infant mortality rate of 19/1000. Some of the general social features contributing to its success are racial and cultural homogeneity, constitutional renunciation of an army, a social-democratic welfare-oriented government since the 1940's and a universal education. In recent decades institutional reorganization included formation of a Central Sanitary Office in the Ministry of Health, a Central Assistance Office, and a Social Security System providing medical and hospital care. In the 1970s all hospitals were placed under Social Security. Now 98.9% of hospitalizations are covered, and 7% of the GDP goes for health care. The epidemiological transition began gradually with sanitation and economic growth in the early 20th century and accelerated with the advent of antibiotics, vaccines, and DDT in the 1940s and 1950s. After a stagnant period in the 1960s due to volcano eruptions, the 1970s saw vast improvements in education, communication, and health infrastructure resulting in control of malaria, tuberculosis, helminthiases, tetanus, measles, diarrheal and respiratory infectious deaths. In the 1970s, primary health care, in the form of quarterly home visits to disadvantaged rural and urban areas, equalized health indices across the country. Immunization reached 95% an sanitation 96% of homes. Secondary health care (outpatient) was extended under Social Security. In this era, fertility fell by half, primarily due to birth spacing and limiting of higher order births. Regression analysis shows that primary health care accounted for 41%, secondary medical care for 32%, socioeconomic progress for 22%, and decline in fertility for 5% of the fall in infant mortality.

Screening practices for cervical and breast cancer in Costa Rica.

Cervical cancer and breast cancer are leading causes of cancer-related morbidity and mortality in Costa Rica. This article reports results of an evaluation of cervical and breast cancer screening practices among Costa Rican women 25 to 58 years old that was based on a nationwide 1984-1985 survey. The evaluation showed that while Pap smears were widely used to screen for cervical cancer, many women did not have their first cervical smear or gynecologic examination until age 30, and that cervical cancer screening was less common among certain high-risk groups, including women with multiple sexual partners and those with high parity. Less than half the women surveyed reported having had a breast examination by a health care provider. Utilization of both cervical cancer and breast cancer screening examinations could be increased by targeting inadequately screened high-risk women through the existing health care system.

Seroepidemiology of chlamydia in Costa Rica.

A population-based study of the sero-epidemiology of chlamydia was performed among a nationally representative sample of 760 Costa Rican women aged 25 to 59 years. Interviews and sera collection were completed between September 1984 and February 1985. The overall seroprevalence of chlamydial antibodies among these women was 56.1%. Women 25 to 39 years of age had a seroprevalence of 51.1%, while women 40 to 59 years of age had a seroprevalence of 64.2%. Women who reported no prior sexual activity had a seroprevalence rate of 48.6%, compared with a seroprevalence rate of 80.7% among women who reported three or more lifetime sexual partners. The geometric mean titre (GMT) of seropositive women ranged from 34.4 among the women who reported no prior sexual activity to 155.0 among the women with three or more lifetime sexual partners. Sero-positivity was more consistently associated with sexual activity than with age. Women with serological evidence of past Herpes simplex virus type 2 (HSV-2) or syphilis infection were more likely to be seropositive than were women without evidence of exposure to these sexually transmitted diseases, even when controlled for age and the number of lifetime sexual partners. The seropositivity among never sexually active women indicates the probable presence of Chlamydia pneumoniae infections, while the high seroprevalence of chlamydial antibodies among the sexually active women suggests that sexually transmitted Chlamydia trachomatis infections represent a public health problem not previously quantified in Costa Rica. Further seroepidemiological and/or culture studies are warranted to determine the incidence and prevalence of sexually transmitted chlamydial infection among men and younger women.

Fertility change in Costa Rica 1960-84: analysis of retrospective lifetime reproductive histories.

Lifetime reproductive histories of a 1984-85 nationally representative sample of 870 women aged 25-59 years provided data to describe the evolution of fertility, contraception, breast-feeding, and natural fecundability in Costa Rica between 1960 and 1984. The contraceptive prevalence rate increased from 23% in 1965 to 58% in 1975 and 66% in 1984. Duration of breast-feeding was stable during the 1960s, decreased in the early 1970s, and increased after about 1976. Fecundability among women who did not practise contraception was lower than expected and declined between 1960 and 1975, probably because of selection effects. Despite a high consistency between estimations from the reproductive histories and other sources of data, some suggestion of omissions of short periods of contraceptive use in the distant past was detected. The survey may have reduced recall errors by using a calendar that summarizes major life events together. The analysis demonstrated the feasibility and usefulness of asking for lifetime reproductive histories in fertility surveys in developing countries.

PIP: Lifetime reproductive histories of a 1984 through 1985 nationally representative sample of 870 women aged 25 through 59 years provided data to describe the evolution of fertility, contraception, breast feeding, and natural fecundity in Costa Rica between 1969 and 1984. The contraceptive prevalence rate increased from 23% in 1965 to 58% in 1975 and 66% in 1984. Duration of breastfeeding was stable during the 1960s, decreased in the early 1970s, and increased after about 1976. Fecundability among women who did not practice contraception was lower than expected and declined between 1960 and 1975, probably because of the selection effects. Despite a high consistency between estimations from the reproductive histories and other sources of data, some suggestion of omissions of short periods of contraceptive use in the distant past was detected. The survey may have reduced recall errors by using a calendar that summarizes major life events together. The analysis demonstrated the feasibility and usefulness of asking for lifetime reproductive histories in fertility surveys in developing countries. Retrospective information gathered on 900 women permitted reconstruction of the results in a a period of dramatic changes. However, Costa Rica may be somewhat exceptional among developing countries because of its high levels of literacy. Some of the few, older, illiterate women may have found a life history calendar difficult to decipher, but others seemed to grasp the approach as easily as did the literate men.

Herpes simplex virus type 2 antibodies: high prevalence in monogamous women in Costa Rica.

We studied the prevalence of antibody to Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) in 766 randomly selected Costa Rican women 25-59 years of age in a national household survey in 1984-1985. Overall, 97.1% were seropositive for HSV-1 and 39.4% for HSV-2. Only 1.1% of HSV-2 seropositive women gave a history of symptomatic genital herpes. HSV-2 virus antibody increased with age and with the number of lifetime sexual partners. HSV-2 seroprevalence among women who reported only 1 lifetime sexual partner was almost twice as high as the prevalence among women who denied sexual experience (30.5% vs. 17.7%) and reached 79.2% among women with greater than or equal to 4 partners. HSV-2 seroprevalence was lower among women whose partners used condoms: 28.9% for those who had used condoms for at least 2 years vs. 44.3% for those who never used condoms.

Cervical cancer risk and use of depot-medroxyprogesterone acetate in Costa Rica.

The relationship between cervical cancer and the use of depot-medroxyprogesterone acetate (DMPA) was examined in a nationwide case-control study in Costa Rica. Cases were women ages 25-58 years of age with invasive squamous cell cancer (N = 149) or carcinoma in situ (CIS, N = 415) reported by the National Tumor Registry during 1982-84. Controls (N = 764) were randomly selected during a nationwide household survey. Using logistic regression, we adjusted for known risk factors for cervical cancer. DMPA use was associated with a risk of CIS of 1.1 (95% confidence interval 0.6-1.8) and a risk of invasive cancer of 1.4 (95% confidence interval 0.6-3.1). The slightly elevated risks observed may be the result of chance or a detection bias. One limitation of this study is that few women had used DMPA for longer than two years.

PIP: A nationwide case-control study was conducted in Costa Rica in 1984-85 to examine the association between depot-medroxyprogesterone acetate (DMPA) and cervical cancer. Cases, restricted to women 25-58 years of age at the time of diagnosis, were women with invasive squamous cell cancer (n = 149) or carcinoma in situ (CIS, n=415) reported by the National Tumor Registry during 1982-84. The 764 controls were randomly selected during a nationwide household survey. On average, the CIS cases were younger than controls; the invasive cases were older than controls. Both case groups were more likely than controls to be of low socioeconomic status, to have become sexually active at a young age, to report a history of a sexually transmitted disease or pelvic inflammatory disease, and to report having 3 or more partners in their lifetime. Ever users of DMPA had a risk of CIS of 1.1 when compared with never users. Women who 1st used DMPA before age 30 had a CIS risk of 0.6 whereas users who began use after age 39 had a risk of 2.0. Both of these risk estimates were based on small numbers of users. Ever users of DMPA had a risk of invasive cancer of 1.4 when compared with never users, but all estimates for invasive cancer were based on only 10 cases who reported use of DMPA. Few of the women had used DMPA for longer than 2 years.

Costa Rica saves infants' lives.

PIP: Even though Costa Rica is underdeveloped economically, life expectancy has been increasing over the past decade and the illiteracy rate was only 7% in 1984. Infant mortality rates have plummeted since 1972 when the 1st national health plan and social security were instituted (pre-1972: 2.3% annual reduction in infant mortality; 1972-1980: 13% decline annually). Decreased risk in the 1st postnatal month of life was responsible for 34% of the decrease from 1972-1980. Control of disease, especially diarrhea and acute respiratory infection, accounted for most of the decline (51%). Immunizations accounted for 8%, prevention of infectious diseases for 10%, control of malnutrition for 5%, and control of death due to premature birth for 14% of the decrease in mortality. Infant death due to pregnancy and delivery complications and congenital defects did not decrease during this period. Socioeconomic conditions normally influence survival rates strongly, but socioeconomic change in Costa Rica during 1970-1980 accounted for only 1/3 of the reduction in infant mortality. These improvements included an increase in the number of educated women, economic growth and decline in fertility (a decrease from 7.6 to 3.4 births between 1960-1980). The majority of the reduction stemmed from utilization of family planning techniques and the reduction of health risk factors. By 1980, the health program initiated in the 1970's provided primary care to 60% of the population, immunized 95% of the children against poliomyelitis, diptheria, pertussis, tetanus, and measles, and by 1984, provided almost all households with a sewage system. Analyses of the impact of socioeconomic development, fertility regulation, hospital care, outpatient services, and primary health care on infant mortality showed that, before 1970, those areas with better economies had a lower mortality rate, and after 1970, the economy and mortality rate had become independent variables. Furthermore, the introduction of health programs in the 1970's correlated with the accelerated decrease in mortality.^ieng

Oral contraceptives and cervical cancer risk in Costa Rica. Detection bias or causal association?

To examine the relationship between cervical cancer and oral contraceptive (OC) use, we analyzed data from a population-based, case-control study in Costa Rica. Women aged 25 to 58 years in whom cervical cancer was diagnosed and reported to the National Tumor Registry were examined as two separate case groups: invasive cervical cancer and carcinoma in situ (CIS). Controls were women aged 25 to 58 years identified through a national survey. Women who had used OCs had no increased risk of invasive cervical cancer compared with women who had never used OCs (relative risk, 0.8; 95% confidence interval, 0.5 to 1.3). Women who had used OCs had an increased risk of CIS compared with those who had never used OCs (relative risk, 1.6; 95% confidence interval, 1.2 to 2.2). However, further analyses indicated that this increased risk was confined to those who had recently used OCs. Also, the risk of CIS was not elevated in subgroups in which a history of cervical smears was not strongly linked to OC use. The elevated risk of CIS among OC users may therefore reflect a bias caused by enhanced detection of disease rather than a causal association.

Reproductive history and breast cancer in a population of high fertility, Costa Rica, 1984-85.

The relationship between breast cancer and women's reproductive history in Costa Rica was analyzed using logistic regression methods on data from 171 breast cancer cases and 826 population-based controls aged 25-58 years. The risk of breast cancer in nulliparous women under age 45 was 3 times that for parous women in the same age group. Women over 44 years of age with a parity greater than 4 had a risk of breast cancer of 0.3 compared to women of the same age but with a parity of 1-4. Neither breast-feeding nor birth interval showed an overall association with breast cancer independent of parity. Women with early age at first birth had a lower relative risk of breast cancer than women aged 20-24 at first birth, but only in two subgroups--women aged 45 and over and women with parity 1-4. Women without a completed pregnancy in the last 20 years had an elevated relative risk. However, results are not conclusive because some information is probably distorted by recall errors. Declines in fertility rates in the 1960s and 1970s may result in an increase of 30% in breast cancer incidence in Costa Rica between 1980 and the year 2000, according to the relative risks found in this study. In contrast, the effect of childlessness will probably not produce significant changes in national breast cancer trends.