Biomedical subjects

M Zack

Publications and source records attributed to M Zack.

At least 19 recordsLinked to original sources

PubMed2004

Low-dose diazepam primes motivation for alcohol and alcohol-related semantic networks in problem drinkers.

Considerable research with animals indicates that the GABA-benzodiazepine (BZ) system plays a key role in alcohol reinforcement. However, only limited research appears to have assessed this issue directly in humans. The present study investigated whether low-dose diazepam would cross-prime motivation for alcohol in problem drinkers. Twelve male problem drinkers (Alcohol Dependence Scale; ADS score > or =9) received oral diazepam (5 mg) and placebo, in a counterbalanced manner on separate sessions. There were three measures of primed motivation for alcohol: self-reported desire for alcohol, consumption of placebo beer in an ostensible taste test procedure, and automatically executed vocal reading responses to Alcohol versus Neutral words on a computer-based task. Diazepam significantly increased beer consumption, and produced a marginally significant increase in reported desire for alcohol. On the reading task, diazepam significantly decreased response latency to Alcohol words relative to Neutral words. Latency to Alcohol words correlated significantly with beer consumption under the drug. Moreover, response latency to Alcohol words under the drug also predicted ADS scores. Thus, severity of dependence was directly linked with vulnerability to a BZ priming effect on motivation for alcohol. These findings provide direct evidence that the GABA-BZ system plays an important role in alcohol reinforcement in problem drinkers.

Administration, Oral↗

PubMed2001

Effects of abstinence and smoking on information processing in adolescent smokers.

RATIONALE: Although adolescent smokers appear to display some of the hallmark features of dependence, the biological and behavioral effects of smoking in this population are poorly understood. OBJECTIVES: This study aimed to define empirically the effects of abstinence and smoking in adolescent smokers, using indices validated in adult smokers. METHODS: Subjects were 16 young novice smokers (five male, 11 female), ages 14-18 years. A modified Stroop task measured the ability to inhibit attention to smoking-related cues; the classic Stroop task measured the ability to inhibit a pre-potent response (i.e. reading a word); a rapid information processing (RIP) task measured vigilance. RESULTS: Abstinence increased and smoking decreased the intrusiveness of smoking cues. Parallel effects were seen in commission errors on the RIP task. These effects were restricted to heavier smokers (>11 cigarettes/day). Subjective withdrawal effects predicted the intrusiveness of smoking words during abstinence. The number of cigarettes smoked per day predicted the beneficial effect of smoking on the classic as well as modified Stroop tasks. The physiological effects of abstinence and smoking predicted RIP performance. CONCLUSIONS: Abstinence impairs and smoking improves inhibitory information processing in young novice smokers in a manner similar to adult smokers. Daily frequency of smoking is a critical moderator of these effects.

Adolescent↗

PubMed2001

Acute subjective and physiological responses to smoking in adolescents.

AIMS: To determine the topography of cigarette smoking and the subjective and physiological effects of abstinence and nicotine in adolescents who smoke on a daily versus a non-daily basis. DESIGN: Repeated measures experiment, non-blinded, involving a single test session. SETTING: Human psychopharmacology laboratory. PARTICIPANTS: Twenty-one daily and 21 non-daily adolescent cigarette smokers (21 females; 21 males; age 13-18 years) with life-time use greater than 10 cigarettes, responding to radio and print advertisements. INTERVENTION: Overnight abstinence from cigarettes followed by smoking of a single cigarette furnished by the participant at test. MEASUREMENTS: The Fagerstrom Test for Nicotine Dependence, saliva nicotine and cotinine, expired air carbon monoxide (CO), heart rate (HR), self-report scales and smoking topography. Most measurements were performed before and after smoking. FINDINGS: Saliva nicotine, CO and HR increased, and self-reported intention and desire to smoke decreased, after smoking (p < 0.001). Fagerstrom scores indicated greater dependence and desire to smoke in daily than in non-daily smokers. HR increased substantially over pre-smoking levels in both groups. Puff topography did not differ between the groups, although collectively these participants appeared to take smaller and more puffs than adult smokers tested under similar conditions. CONCLUSION: This study provides initial evidence that adolescent cigarette smokers self-administer physiologically active doses of nicotine very early in their smoking careers. Nicotine dependence in adolescents appears to be a function of the current frequency of cigarette use, and subjective-behavioral consequences of abstinence and smoking are evident even in non-daily smokers.

Adolescent↗

PubMed2001

Risk factors for subsequent invasive breast cancer and breast cancer death after ductal carcinoma in situ: a population-based case-control study in Sweden.

In a case-control study derived from a cohort of 4661 women with a primary carcinoma in situ of the breast, we investigated age at diagnosis, mode of detection, tumor characteristics, and primary therapy, as prognostic factors for developing invasive breast cancer or dying from breast cancer. From all of the women with a primary carcinoma in situ reported to the Swedish Cancer Registry from 1960 through 1992, we selected as cases all of the women with a ductal carcinoma in situ who later died of breast cancer (n = 39) or who developed a subsequent invasive cancer in either breast (n = 118). From this cohort, we also selected controls matched to the cases by year of diagnosis and health care region. We conducted univariate and multivariate analyses to study the association between risk of invasive cancer or death and the different risk factors. Large size, diameter > or = 25 mm [odds ratio (OR), 3.5; 95% confidence interval (CI), 1.1-11.4] and multifocality (OR, 3.9; 95% CI, 1.2-12.7) increased the risk of breast cancer death in univariate analysis. Postoperative radiotherapy (OR, 0.1; 95% CI, 0.0-1.0) and mastectomy (OR, 0.1-95% CI, 0.0-0.5) lowered the risk of an ipsilateral invasive cancer in multivariate analysis. The risk pattern by treatment category differed between those who had an ipsilateral invasive cancer and those who either had a contralateral cancer or died from breast cancer. The driving forces behind local and generalized disease may differ. Because confounding by indication may influence the effects of different treatments, the results should be interpreted with caution.

Adult↗

PubMed2000

Breast cancer risk and lifetime leisure-time and occupational physical activity (Sweden).

OBJECTIVE: To clarify whether type and timing of physical activity affect postmenopausal breast cancer risk. METHODS: In a population-based case-control study within the Swedish female population 50-74 years of age, 3347 women with invasive, postmenopausal breast cancer (84% of all eligible) and 3455 controls (82% of all selected) reported on past leisure-time physical activity. Record linkage to decennial census data (1960-1990) provided estimates of their occupational physical activity. Odds ratios with 95% confidence intervals were estimated by multivariate logistic regression. RESULTS: After adjustment for potential confounders, women in sedentary occupations during their reproductive years (25-44 years of age) had a 50% higher risk for postmenopausal breast cancer, compared to those with the physically most demanding jobs. Only the most recent leisure-time physical activity was associated with a significant risk reduction. Women with the combination of sedentary jobs and lack of leisure-time exercise had a three-fold higher risk of breast cancer, compared to the physically most active both inside and outside the workplace. CONCLUSION: Effects of occupational and leisure-time physical activity on breast cancer risk appear to have different latency times, and/or to be effect-modified by age or reproductive status. Although chance might explain our findings, it is advisable to consider type and timing of physical activity in future studies.

Adult↗

PubMed1999

Implicit activation of alcohol concepts by negative affective cues distinguishes between problem drinkers with high and low psychiatric distress.

This study tested the hypothesis that negative affective (NEG) cues activate alcohol concepts more strongly in problem drinkers with high rather than low psychiatric distress (PD) and that a parallel difference applies to activation of NEG concepts by alcohol cues. A lexical decision task assessed memory activation in 36 problem drinkers with high vs. low scores on the Symptom Checklist-90. High PD drinkers displayed activation in each condition; low PD drinkers displayed inhibition. Activation of alcohol concepts by NEG cues correlated with intensity of PD, bias to drink in NEG states, and confidence to avoid drinking in these states. Results corroborate in vivo cue reactivity studies and indicate a functional difference between problem drinkers with high and low PD.

Adult↗

PubMed1999

Reinforcement of a behavioral standard modifies individual differences under alcohol.

OBJECTIVE: Whether alcohol increases or decreases individual differences relative to sober levels may depend on the situation in which behavior is measured. This study tested the hypothesis that reinforcement and behavioral standards will modify the effects of alcohol on individual differences. METHOD: Two groups of male social drinkers (N = 12) performed a psychomotor task under repeated doses of alcohol (0.62 g/kg), and received verbal feedback (FB) for matching an easy or a difficult performance standard. RESULTS: FB reduced between-subject and within-subject differences under alcohol, especially when coupled with the easy standard. Between-subject and within-subject differences were equivalent under alcohol and sober conditions when variance introduced by changing blood drug concentrations was controlled. The consistency of an individual's performance across doses depended on the consistency of his criterion response. CONCLUSIONS: Situational factors alter individual differences under alcohol, and pharmacological intoxication alone does not appear to account for undue variability in behavior under moderate doses.

Adult↗

PubMed1999

Clinical use of benzodiazepines and decreased memory activation in anxious problem drinkers.

Clinical use of benzodiazepines (BZDs) may improve treatment outcome in anxious problem drinkers. Decreased activation of alcohol-related memories by negative affective cues may partly explain the beneficial effects of BZDs. To explore this possibility, the present study assessed semantic priming of alcohol words by negative affective words in anxious problem drinkers who received their standard dose of BZD and in unmedicated controls. Two groups of nine subjects each were matched on levels of anxiety, alcohol use, and alcohol dependence before performing a lexical decision task. Medicated subjects displayed significantly less activation than did unmedicated subjects on trials containing negative affective primes and alcohol-related targets, but displayed equivalent activation on control trials with neutral, categorized words. Degree of activation also correlated with a drug's affinity for the BZD receptor. These preliminary results suggest that BZD-induced amnesia may contribute to the therapeutic effects of these drugs in anxious problem drinkers.

Adult↗

PubMed1999

Beta-carotene intake and risk of postmenopausal breast cancer.

We assessed the relation between beta-carotene consumption at various times in life and breast cancer risk by conducting a case-control study nested within a population-based cohort of women screened for breast cancer in Sweden. We conducted a telephone interview with 273 incident breast cancer cases and 371 controls about their diet at various ages throughout their lifetime. Controls were frequency matched to cases on age, month and year of mammography, and county of residence. We used unconditional logistic regression to measure the association between beta-carotene intake and breast cancer risk while adjusting for total energy intake, recency of intake, and the matching variables. Women were at lower risk with increasing levels of reported intake of beta-carotene. This pattern of association between breast cancer and beta-carotene intake was similar at various times before screening. These findings indicate that although diets high in beta-carotene may be associated with lower breast cancer risk, there does not seem to be evidence of a critical time period during which such diets are more relevant.

Breast Neoplasms↗

PubMed1998

The SCL-90 factor structure in comorbid substance abusers.

Previous research has shown that the SCL-90 predicts response to treatment by substance abusers. However, the construct validity of the subscales has been questioned. The present study assessed the factor structure of the SCL-90 in 740 outpatients with coexisting substance use and nonsubstance use psychiatric disorders. The congruency coefficient and salient similarity index tested factorial invariance across gender. Exploratory factor analyses assessed the scale's empirical factor structure. The pattern of loadings for the first three factors was congruent in each gender. The factor analysis yielded three inter-correlated factors that together accounted for 38% of the variance in ratings from the entire sample. A single higher-order factor was identified that explained 60% of the variance in factor scores. These findings are consistent with previous studies that obtained a single predominant factor, and suggest that the SCL-90 primarily taps general psychiatric distress in comorbid substance abusers.

Adult↗

PubMed1998

Trends in colorectal cancer incidence in Sweden 1959-93 by gender, localization, time period, and birth cohort.

OBJECTIVES: This study examined invasive colorectal cancer incidence-rates in Sweden from 1959 through 1993 (n = 134,643 cases). METHODS: Age-standardized rates were calculated using the Swedish population in 1970 as a reference. RESULTS: In right-sided colon cancer (ascending and transverse colon including right and left flexures), male age-standardized rates rose from 8.0 to 15.0 (1.8 percent annually, 95 percent confidence interval [CI] = 1.3-2.4) and female rates increased from 9.1 to 14.4 (1.5 percent annually, CI = 1.0-2.0). For left-sided colon cancer (descending and sigmoid colon), the rates have been stable recently. For rectal cancer, the rates among men rose from 18.8 to 23.0 and among women from 10.7 to 14.7. For both men and women, the relative risk (RR) of right-sided colon cancer had been increasing in successive generations, until leveling-off in those born after 1930. The RR of left-sided colon cancer had been almost constant for cohorts born before 1930 but steadily decreasing in later-born cohorts. The RR of rectal cancer was slightly increasing in successive cohorts. CONCLUSIONS: Changes in lifestyle or carcinogenic exposures during early life probably explain Swedish colorectal cancer incidence-trends better than improved diagnostic activities.

Adult↗

PubMed1997

International incidence rates of invasive cervical cancer after introduction of cytological screening.

Because Pap-smear screening can detect pre-invasive cervical cancer, such screening can markedly reduce the occurrence of invasive cancer. However, its impact in different populations is uncertain. This study compares the changes in cervical cancer incidence at different ages after the introduction of screening in different populations, and addresses the impact of organized and opportunistic smear taking. We identified 17 cancer registries large enough and existing long enough to analyze screening effects. For each registry, we calculated the relative reduction in age-specific incidence rates and in incidence rates age-standardized to the world population after the introduction of cytologic screening. In 11 of the 17 populations, age-standardized incidence rates declined markedly from 27 percent in Norway and to 77 percent in Finland. Age-specific declines were confined to women aged 30 to 70 years old with a nadir around ages 40 to 55. In six other populations, age-standardized incidence rates declined less than 25 percent, an amount too small to provide unambiguous evidence of a screening effect. In several populations, cytologic screening had a more pronounced effect than is generally recognized. Because age-specific declines in cervical cancer incidence rates were strikingly similar in populations with widely different screening practices, organized screening may not be markedly superior to opportunistic screening. The reduction in reported cancer incidence because of screening is smaller in younger and older women.

Adult↗

PubMed1997

Drunk or sober? Learned conformity to a behavioral standard.

OBJECTIVE: This research tested the hypothesis that behavioral standards in a drinking situation are learned. METHOD: Two groups of male social drinkers (N = 12) were reinforced with verbal feedback (FB) for matching either a "sober" (S) or an "intoxicated" (I) behavioral standard under repeated doses (0.62 g/kg) of alcohol. The criterion measure was time to perform a trial on a psychomotor tracking task. A fast, efficient time (115 seconds) defined the S standard. A slow, inefficient time (150 seconds) defined the I standard. The behavioral effect of standards was tested during a final FB training session under alcohol, and during retention under a placebo and under alcohol, with FB absent. RESULTS: S and I groups approximated their respective standards when reinforced, and these standards were retained when reinforcement was subsequently withheld. Under placebo, group S displayed sober performance comparable to their drug-free baseline, whereas Group I's performance was significantly impaired. These group differences remained significant under alcohol, and the drug effect impaired each group's performance to a similar degree. CONCLUSIONS: Prior reinforcement of a standard under alcohol can lead to the display of that standard when alcohol is expected or received. The consistent difference in the groups' performance under placebo and under alcohol suggests that learned standards may add an effect on behavior in a drinking situation that is distinct from the drug effect. Retention of group standards under alcohol in the absence of reinforcement confirms that these standards were learned and were not simply a response to situational demand.

Adult↗

PubMed1996

Maternal and perinatal factors associated with non-Hodgkin's lymphoma among children.

This nested case-control study based on 1.7 million live births in Sweden explores the associations between maternal and perinatal factors and the occurrence of childhood non-Hodgkin's lymphoma (NHL). The National Swedish Cancer Registry ascertained 168 cases in successive birth cohorts from 1973 through 1989 recorded in the Swedish Medical Birth Registry. From the nationwide Birth Registry, 5 controls without NHL and alive at the date the case was diagnosed were randomly selected from the pool of children, with each case matched by gender, birth year and birth month. Standardized information on selected maternal and perinatal factors up to one month after delivery were recorded in the Medical Birth Registry. Mothers of children with NHL were more likely than mothers of controls to have undergone Cesarean section [Odds ratio (OR) 1.6] and to have been exposed to paracervical anesthesia during delivery (OR 1.8). Children with NHL were more likely than controls to have endocrine-metabolic disorders (OR 3.3). This study is one of the largest focusing on the etiology of childhood NHL. Most of the maternal and perinatal characteristics studied did not markedly affect risk for childhood NHL, which may be due to maternal and perinatal factors not included in these data or to exposures later in life.

Adolescent↗

PubMed1996

Maternal and perinatal risk factors for childhood brain tumors (Sweden).

Childhood brain tumors (CBT) include a diversity of rare neoplasms of largely unknown etiology. To assess possible maternal and perinatal risk factors for CBT according to subtype, we carried out a nested (within Swedish birth-cohorts, 1973-89) case-control study, utilizing data from the nationwide Birth Registry. We ascertained incident brain tumor cases through linkage of the nationwide Birth and Cancer Registries and randomly selected five living controls from the former, matching each case on gender and birthdate. There were 570 CBT cases, including 205 low grade astrocytomas, 58 high grade astrocytomas, 93 medulloblastomas, 54 ependymomas, and 160 'others.' Risks for all brain tumors combined were elevated in relation to: (i) three maternal exposures-oral contraceptives prior to conception (odds ratios [OR] = 1.6, 95 percent confidence interval [CI] = 1.0-2.8), use of narcotics (OR = 1.3, CI = 1.0-1.6), or penthrane (OR = 1.5, CI = 1.1-2.0) during delivery); (ii) characteristics of neonatal distress (a combined variable including low one-minute Apgar score, asphyxia [OR = 1.5, CI = 1.1-2.0]) or treatments for neonatal distress (use of supplemental oxygen, ventilated on mask, use of incubator, scalp vein infusion, feeding with a jejunal tube [OR = 1.6, CI = 0.9-2.6]); and (iii) neonatal infections (OR = 2.4, CI = 1.5-4.0). Higher subtype-specific risks, observed for a few risk factors, did not differ significantly from the risk estimates for all subtypes combined for the corresponding risk factors. Childhood brain tumors were not associated significantly with other maternal reproductive, lifestyle, or disease factors; perinatal pain, anesthetic medications, birth-related complications; or with birthweight, birth defects, or early neonatal diseases. These findings suggest several new leads, but only weak evidence of brain tumor subtype-specific differences.

Adjuvants, Anesthesia↗

PubMed1996

A search for recall bias in a case-control study of diet and breast cancer.

BACKGROUND: In retrospective studies of dietary habits and breast cancer risk, recall bias is a concern since diet has been publicized as a cause of breast cancer. METHODS: In a case-control study of diet and breast cancer risk nested within a cohort of women screened with mammography, we contrasted answers to a retrospective dietary interview with answers to a dietary questionnaire which was filled out before any diagnostic procedures for breast cancer were undertaken. The source population was all women aged 40-74 in two counties in Sweden invited to mammographic screening and asked to fill out a questionnaire before the screening. Cases and controls were subsequently defined -- matched on age, county of residence, and time of mammography -- and approached for an interview. RESULTS: In all, 265 cases and 431 controls participated in the study. Means of frequencies differed between the agreement in the questionnaire's and the interview's classifications of study subjects into quartiles of monthly intake varied between 31 percent and 57 percent. Kappa statistics in all food groups were below 0.41. In a regression analysis, case subjects with low responses on the questionnaire about intake of meat, snacks, and coffee and tea gave higher responses on interview than did controls who had low questionnaire responses for these food groups. The reverse was also true: cases' responses that were high on the questionnaire were lower on interview for these food groups than were controls' responses. CONCLUSIONS: We found few signs of recall bias, and the few indications of a differential misclassification that we found were not in food groups that have been publicly discussed as causes of breast cancer.

Adult↗

PubMed1995

Alcohol intake and breast cancer risk: effect of exposure from 15 years of age.

Research regarding the relationship between alcohol intake and breast cancer risk has suggested an association between the two, although the data are inconsistent regarding dose effects and susceptible populations. To clarify these issues, we investigated the association of breast cancer risk with alcohol intake at various ages in a population-based case-control study nested within a screening cohort in Sweden. Subjects were women 40-75 years old who participated in a screening program in central Sweden. Information about personal characteristics, diet, and alcohol intake was obtained by a questionnaire sent out at the invitation to the screening interview and at a supplementary interview conducted among a sample of women who did and did not develop breast cancer. Alcohol intake did not affect breast cancer risk among women under 50 years old. However, among those over 50 years of age, ever-drinking conferred a relative risk of 1.8 (95% confidence interval = 1.2-2.6). Current and former drinkers had similar increases in risk. No particular latent period of alcohol effect was identified, but drinking later in life to have a bigger effect than did drinking earlier in life.

Adolescent↗

PubMed1994

Diet and breast cancer risk. Results from a population-based, case-control study in Sweden.

BACKGROUND: We describe an epidemiologic analytical study of the relationship between current diet and breast cancer risk. METHOD: The study design is a case-control analysis. Cases were recruited from a mammography screening program used within the national health care system; the control subjects were selected from subjects free of breast cancer in the same population. A total of 380 cases and 525 control subjects, frequency-matched for age, month of mammography, and county of residence, were identified. Of these, 265 cases and 432 control subjects were included in this analysis. Odds ratios for breast cancer in relation to food and nutrient intake were the main outcome measures. RESULTS: Exposure in the highest quartile of beta-carotene intake gave an odds ratio of 0.6 (95% confidence interval, 0.4 to 1.0). No increased risk was noted with high fat intake. Breast cancer risk was associated with alcohol intake only when alcohol was analyzed in quartiles: odds ratio, 1.6 (95% confidence interval, 1.0 to 2.4) for the highest quartile of intake vs the lowest. Stratified analyses showed that a high fat intake might decrease the protective effect of beta-carotene intake. Risks did not change appreciably with adjustment for total energy intake or known breast cancer risk factors. CONCLUSIONS: As in most other studies, no strong risk factors for breast cancer have been identified in the current diet. The negative association between breast cancer risk and beta-carotene intake may be supported by a plausible mechanism, but our finding concerning alcohol should be interpreted cautiously since there was no dose-response relationship and the biological mechanism for a threshold effect at very low levels of consumption is unclear.

Adult↗