How many cases of Type 2 diabetes mellitus are due to being overweight in middle age? Evidence from the Midspan prospective cohort studies using mention of diabetes mellitus on hospital discharge or death records

AIMS

To relate body mass index (BMI) in middle age to development of diabetes mellitus.

METHODS

Participants were 6927 men and 8227 women from the Renfrew/Paisley general population study and 3993 men from the Collaborative occupational study. They were aged 45-64 years and did not have reported diabetes mellitus. Cases who developed diabetes mellitus, identified from acute hospital discharge data and from death certificates in the period from screening in 1970-1976 to 31 March 2004, were related to BMI at screening.

RESULTS

Of Renfrew/Paisley study men 5.4%, 4.8% of women and 5% of Collaborative study men developed diabetes mellitus. Odds ratios for diabetes mellitus were higher in the overweight group (BMI 25 to < 30 kg/m(2)) than in the normal weight group (BMI 18.5 to < 25 kg/m(2)) and highest in the obese group (BMI >or= 30 kg/m(2)). Compared with the normal weight group, age-adjusted odds ratios for overweight and obese Renfrew/Paisley men were 2.73 [95% confidence interval (CI) 2.05, 3.64] and 7.26 (95% CI 5.26, 10.04), respectively. Further subdividing the normal, overweight and obese groups showed increasing odds ratios with increasing BMI, even at the higher normal level. Assuming a causal relation, around 60% of cases of diabetes could have been prevented if everyone had been of normal weight.

CONCLUSIONS

Overweight and obesity account for a major proportion of diabetes mellitus, as identified from hospital discharge and death records. With recent increases in the prevalence of overweight, the burden of disease related to diabetes mellitus is likely to increase markedly. Primordial prevention of obesity would be a major strategy for reducing the incidence of diabetes mellitus in populations.

Obesity and use of acute hospital services in participants of the Renfrew/Paisley study

BACKGROUND

Because overweight and obesity are associated with comorbidities, increasing levels of overweight and obesity may impact on hospital use.

METHODS

Body mass index (BMI) in middle age was related to acute hospital use in 7036 men and 8327 women from the Renfrew/Paisley prospective cohort study in Scotland. Participants in this general population study were examined between 1972 and 1976 when aged 45-64 years. Acute hospital admissions and bed days per 1000 person-years were calculated by the World Health Organization BMI categories in the follow-up period to 31 March 2004.

RESULTS

Underweight and normal weight men had lower-than-expected admission rates, and overweight and obese men had higher-than-expected admission rates. Obese men had higher-than-expected bed day rates. For women, there was a U-shaped relationship with admission rate, with normal weight women having the lowest admission rate and underweight and obese women having similar high rates. Underweight and obese women had higher-than-expected bed day rates.

CONCLUSIONS

Participants who were obese in midlife had more-than-expected acute hospital admissions and in particular more bed days. With levels of obesity increasing since this study was started in the 1970s, if these patterns persist, there may be increasing demand on health service resources.

Effects of baclofen on cocaine self-administration: opioid- and nonopioid-dependent volunteers

Preclinical and clinical studies suggest that GABAB receptor agonists selectively decrease cocaine use. The behavioral mechanism for the interaction between baclofen and cocaine in humans is not known, nor have its effects been characterized in individuals dependent on both cocaine and methadone. The objective of this study is to determine how maintenance on baclofen influences smoked cocaine's reinforcing and subjective effects, mood and cocaine craving prior to and after the initiation of cocaine use in cocaine-dependent volunteers with and without concurrent opioid dependence. Nontreatment-seeking volunteers (10 nonopioid dependent; seven methadone maintained), residing on an in-patient research unit for 21 days, were maintained on each baclofen dose (0, 30, 60 mg po) for 7 days. A smoked cocaine dose-response curve (0, 12, 25, 50 mg) was determined twice: on days 3-4 and days 6-7 of each baclofen maintenance condition. Cocaine sessions began with a sample trial, when participants smoked the cocaine dose available that session, and five choice trials, when participants chose between smoking the available cocaine dose or receiving one 5 dollars merchandise voucher. The results show that in the nonmethadone group, baclofen (60 mg) decreased self-administration of a low cocaine dose (12 mg). In the methadone group, baclofen decreased craving for cocaine. In both groups, baclofen decreased cocaine's effects on heart rate. Baclofen did not alter cocaine's robust subjective effects (eg 'High,' 'Stimulated') for either group. The results from this laboratory study appear consistent with clinical evidence showing that baclofen decreases cocaine use in nonopioid-dependent patients seeking treatment for cocaine dependence. The distinct pattern of effects in methadone-maintained participants suggests baclofen may not be effective in opioid-dependent cocaine users.

Modafinil attenuates disruptions in cognitive performance during simulated night-shift work

Common complaints among shift workers are sleep disruptions and increased sleepiness while working, which may contribute to shift workers being more susceptible to diminished performance and work-related accidents. The purpose of this double-blind, within-participant study was to examine the effects of the alerting agent modafinil on cognitive/psychomotor performance, mood, and measures of sleep during simulated shift work. In all, 11 participants completed this 23-day residential laboratory study. They received a single oral modafinil dose (0, 200, 400 mg) 1 h after waking for three consecutive days under two shift conditions: day shift and night shift. Shifts alternated three times during the study, and shift conditions were separated by an 'off' day. When participants received placebo, cognitive performance and subjective ratings of mood were disrupted during the night shift, relative to the day shift. Objective and subjective measures of sleep were also disrupted, but to a lesser extent. Modafinil reversed disruptions in cognitive performance and mood during the night shift. While modafinil produced few effects on sleep measures during the night shift, the largest dose produced several sleep alterations during the day shift. These data demonstrate that abrupt shift changes produced cognitive performance impairments and mood disruptions during night shift work. Therapeutic doses of modafinil attenuated night-shift-associated disruptions, but the larger dose produced some sleep impairments when administered during day-shift work.

A population study of the long-term consequences of Rose angina: 20-year follow-up of the Renfrew-Paisley study

OBJECTIVE

To examine the long-term cardiovascular consequences of angina in a large epidemiological study.

DESIGN

Prospective cohort study conducted between 1972 and 1976 with 20 years of follow-up (the Renfrew-Paisley Study).

SETTING

Renfrew and Paisley, West Scotland, UK.

PARTICIPANTS

7048 men and 8354 women aged 45-64 years who underwent comprehensive cardiovascular screening at baseline, including the Rose Angina Questionnaire and electrocardiography (ECG).

MAIN OUTCOME MEASURES

All deaths and hospitalisations for cardiovascular reasons occurring over the subsequent 20 years, according to the baseline Rose angina score and baseline ECG.

RESULTS

At baseline, 669 (9.5%) men and 799 (9.6%) women had angina on Rose Angina Questionnaire. All-cause mortality for those with Rose angina was 67.7% in men and 43.3% in women at 20 years compared with 45.4% and 30.4%, respectively, in those without angina (p<0.001). Values are expressed as hazards ratio (HR) (95% confidence interval (CI). In a multivariate analysis, men with Rose angina had an increased risk of cardiovascular death or hospitalisation (1.49 (1.33 to 1.66), myocardial infarction (1.63 (1.41 to 1.85)) or heart failure (1.54 (1.13 to 2.10)) compared with men without angina. The corresponding HR (95% CI) for women were 1.38 (1.23 to 1.55), 1.56 (1.31 to 1.85) and 1.92 (1.44 to 2.56). An abnormality on the electrocardiogram (ECG) increased risk further, and both angina and an abnormality on the ECG increased risk most of all compared with those with neither angina nor ischaemic changes on the ECG. Compared with men, women with Rose angina were less likely to have a cardiovascular event (0.54 (0.46 to 0.64)) or myocardial infarction (0.44 (0.35 to 0.56)), although there was no sex difference in the risk of stroke (1.11 (0.75 to 1.65)), atrial fibrillation (0.84 (0.38 to 1.87)) or heart failure (0.79 (0.51 to 1.21)).

CONCLUSIONS

Angina in middle age substantially increases the risk of death, myocardial infarction, heart failure and other cardiovascular events.

Effect of socioeconomic deprivation on the population risk of incident heart failure hospitalisation: an analysis of the Renfrew/Paisley Study

BACKGROUND

There are few data describing the effect of socioeconomic deprivation on the risk of developing heart failure (HF).

AIMS

To examine the relationship between socioeconomic deprivation and hospitalisation with HF over 20 years.

METHODS

Between 1972 and 1976, 15,402 individuals, aged 45-64 years, residing in two towns in Scotland, underwent cardiovascular screening. We report hospitalisations with HF over the subsequent 20 years according to Carstairs deprivation category and Social Class.

RESULTS

Following screening, 628 men and women (4.1%) were hospitalised with a primary diagnosis of HF. There was a gradient in the risk of HF hospitalisation with increasing socioeconomic deprivation (P=0.003). Of the most deprived individuals, 6.4% were hospitalised for HF compared to 3.5% of the most affluent group. Cox-proportional Hazard models showed that independent of age, sex and baseline risk factors for cardio-respiratory status, greater socioeconomic deprivation increased the risk of HF admission (P<0.001, overall). The adjusted risk of admission for HF was 39% greater in the most versus least deprived subjects (RR 1.39 95% CI 1.04-2.01; P=0.04).

CONCLUSION

These data show a link between social deprivation and the risk of developing HF, irrespective of baseline cardio-respiratory status and cardiovascular risk factors.

Childhood IQ of parents related to characteristics of their offspring: linking the Scottish Mental Survey 1932 to the Midspan Family Study

The objective of the study was to investigate the relationship between childhood IQ of parents and characteristics of their adult offspring. It was a prospective family cohort study linked to a mental ability survey of the parents and set in Renfrew and Paisley in Scotland. Participants were 1921-born men and women who took part in the Scottish Mental Survey in 1932 and the Renfrew/Paisley study in the 1970s, and whose offspring took part in the Midspan Family study in 1996. There were 286 offspring from 179 families. Parental IQ was related to some, but not all characteristics of offspring. Greater parental IQ was associated with taller offspring. Parental IQ was inversely related to number of cigarettes smoked by offspring. Higher parental IQ was associated with better education, offspring social class and offspring deprivation category. There were no significant relationships between parental IQ and offspring systolic blood pressure, diastolic blood pressure, cholesterol, glucose, lung function, weight, body mass index, waist hip ratio, housing, alcohol consumption, marital status, car use and exercise. Structural equation modelling showed parental IQ associated with offspring education directly and mediated via parental social class. Offspring education was associated with offspring smoking and social class. The smoking finding may have implications for targeting of health education.

Increasing treatment options for cannabis dependence: a review of potential pharmacotherapies

Despite the fact that rates of cannabis dependence have increased substantially over the past several years, there are no medications approved for the treatment of cannabis dependence. This paper reviews data from recent research on cannabinoids that may be relevant for the development of pharmacotherapies for cannabis dependence. Included in the discussion are findings from studies that have assessed the ability of medications to ameliorate cannabis-related abstinence symptoms in laboratory animals and human research participants. Data from studies that have investigated the effects of pharmacological agents on cannabis self-administration are also reviewed because these data may provide information critical for informing relapse prevention medication development efforts. The majority of published studies evaluating cannabis pharmacotherapies have focused on decreasing withdrawal symptoms: a growing number of medications reduce symptoms in laboratory animals, but the majority of these medications have not been tested in humans. Fewer studies have assessed the effects of potential cannabis treatment medications on cannabinoid-related reinforcing effects. In laboratory animals, only the CB1 cannabinoid antagonist rimonabant has shown promise. In humans, this medication has not been tested on cannabis reinforcing effects. To date, no medication has been shown to alter cannabis self-administration by humans.

Combined effects of methamphetamine and zolpidem on performance and mood during simulated night shift work

Individuals who work irregular or rotating shifts often use stimulants and sedatives to offset shift-change-related mood and performance decrements. During this simulated shift work study the acute effects of the stimulant, methamphetamine were examined, and the effects of the hypnotic, zolpidem, and the combination were assessed during the shift after drug administration. Eight volunteers completed this 21-day, within-participant, residential laboratory study during which they received a single oral methamphetamine dose (0 or 10 mg) 1 h after waking, i.e., before task performance, and a single oral zolpidem dose (0 or 10 mg) 1 h before bedtime under 2 shift conditions: day shift and night shift. When participants received placebo at both dosing times, performance on some psychomotor tasks (e.g., the digit-symbol substitution task) and on some measures of mood (e.g., ratings of "Energetic") were disrupted during the night shift, relative to the day shift. Methamphetamine alone eliminated virtually all shift-related disruptions, while zolpidem alone and the drug combination produced few effects. These data indicate that shift changes produce performance impairments and mood alterations that are improved by a single low to moderate dose of methamphetamine. Zolpidem, given alone or in combination with methamphetamine, did not alleviate most shift-change mood and performance effects.

Long-term cardiovascular consequences of obesity: 20-year follow-up of more than 15 000 middle-aged men and women (the Renfrew-Paisley study)

AIMS

To examine the long-term cardiovascular consequences of obesity and project the cardiovascular consequences of the recent increase in prevalence of obesity.

METHODS AND RESULTS

Between 1972 and 1976, 15 402 individuals aged 45-64, living in two towns in the west of Scotland underwent comprehensive cardiovascular screening. We analysed all deaths and hospitalizations for cardiovascular reasons occurring over the subsequent 20 years according to baseline body mass index (BMI) category. Compared with normal weight individuals (BMI 18.5-24.9), obesity (BMI > or =30) was associated with an increased adjusted risk of coronary heart disease (hazard ratio for death or hospital admission: 1.60, 95% CI 1.45-1.78), heart failure (2.09, 1.68-2.59), stroke (1.41, 1.21-1.65), venous thrombo-embolism (2.29, 1.60-3.30), and atrial fibrillation (1.75, 1.17-2.65). Obesity was associated with nine additional cardiovascular deaths and 36 additional cardiovascular hospital admissions for every 100 affected middle-aged men over the subsequent 20 years (seven deaths and 28 admissions in women). Assuming no change in cardiovascular risk profile and outcomes related to obesity, the increase in prevalence in 1998, when compared with 1972, is projected to lead to an additional four cardiovascular deaths and 14 admissions per 100 middle-aged men and women over the next 20 years.

CONCLUSION

Obesity is associated with an increase in a broad range of fatal and non-fatal cardiovascular events. Consideration of only coronary, only fatal, and only first events greatly underestimates the cardiovascular consequences of obesity.

Reinforcing effects of oral Delta9-THC in male marijuana smokers in a laboratory choice procedure

RATIONALE

Oral Delta-9-tetrahydrocannabinol (Delta(9)-THC; Marinol) is medically available for the treatment of nausea associated with cancer chemotherapy and for wasting syndromes related to HIV/AIDS. Little is known about its reinforcing effects.

OBJECTIVE

This study was conducted to characterize the reinforcing effects of oral Delta(9)-THC in experienced marijuana smokers under controlled laboratory conditions.

METHODS

Ten healthy male marijuana users completed this 17-day residential study. On days 2, 6, 10, and 14, at 0900 h, participants received a "sample" oral dose of Delta(9)-THC (0, 10, 20 mg) and an alternative reinforcer, a 2 US dollars voucher (redeemable for cash at study's end). Over the next 3 days, they had 11 opportunities to self-administer either the sampled dose of Delta(9)-THC or to receive a 2 US dollars voucher.

RESULTS

Participants chose active Delta(9)-THC (10 and 20 mg) more often than placebo (<two selections vs approximately four selections, respectively). However, they chose active Delta(9)-THC on less than 50% of choice opportunities. Both active Delta(9)-THC doses produced significant increases in "positive" subjective effects, impaired psychomotor performance, and increased heart rate, relative to the placebo conditions.

CONCLUSION

These data indicate that oral Delta(9)-THC may have modest abuse liability in experienced marijuana smokers.

An evaluation of the reinforcing effects of memantine in cocaine-dependent humans

The purpose of this double-blind, outpatient study was to evaluate the reinforcing and subjective effects of the uncompetitive N-methyl-d-aspartate (NMDA) antagonist memantine in cocaine-dependent humans. Eight participants (two females, six males) completed this study which consisted of three blocks of seven sessions; each block tested a different dose of memantine. During the first two sessions of each block, participants "sampled" the memantine capsule (10, 20, or 30 mg) and the placebo capsule that were available for the next five sessions. During the five subsequent sessions, participants had an opportunity to self-administer either the active or placebo capsule. Memantine was not reinforcing and subjective-effects ratings were not altered as a function of dose. Results suggest that these doses of memantine do not have abuse liability in cocaine-dependent individuals.

Carboxyhaemoglobin concentration, smoking habit, and mortality in 25 years in the Renfrew/Paisley prospective cohort study

OBJECTIVE

To investigate how carboxyhaemoglobin concentration is related to smoking habit and to assess whether carboxyhaemoglobin concentration is related to mortality.

DESIGN

Prospective cohort study.

SETTING

Residents of the towns of Renfrew and Paisley in Scotland.

PARTICIPANTS

The whole Renfrew/Paisley study, conducted between 1972 and 1976, consisted of 7048 men and 8354 women aged 45-64 years. This study was based on 3372 men and 4192 women who were screened after the measurement of carboxyhaemoglobin concentration was introduced about halfway through the study.

MAIN OUTCOME MEASURES

Deaths from coronary heart disease (CHD), stroke, chronic obstructive pulmonary disease (COPD), lung cancer, and all causes in 25 years after screening.

RESULTS

Carboxyhaemoglobin concentration was related to self reported smoking and for each smoking category was higher in participants who reported inhaling than in those who reported not inhaling. Carboxyhaemoglobin concentration was positively related to all causes of mortality analysed (relative rates associated with a 1 SD (2.93) increase in carboxyhaemoglobin for all causes, CHD, stroke, COPD, and lung cancer were 1.26 (95% confidence interval (CI) 1.19 to 1.34), 1.19 (95% CI 1.13 to 1.26), 1.19 (95% CI 1.13 to 1.26), 1.64 (95% CI 1.47 to 1.84), and 1.69 (95% CI 1.60 to 1.79), respectively). Adjustment for self reported cigarette smoking attenuated the associations but they remained relatively strong.

CONCLUSIONS

Self reported smoking data were validated by the objective measure of carboxyhaemoglobin concentration. Since carboxyhaemoglobin concentration remained associated with mortality after adjustment for smoking, carboxyhaemoglobin seems to capture more of the risk associated with smoking tobacco than does self reported tobacco consumption alone. Analysing mortality by self reported cigarette smoking underestimates the strength of association between smoking and mortality.

Sleep quality deteriorates over a binge--abstinence cycle in chronic smoked cocaine users

RATIONALE

In cocaine dependent individuals, changes in subjective and objective sleep quality accompany their characteristic binge-abstinence cycle. Preliminary studies suggest that sleep quality may decline with prolonged abstinence. Reported here are results of the most extensive study to date on sleep abnormalities during cocaine binge and confirmed abstinence under controlled conditions.

OBJECTIVES

The purpose of the current study was to use an experimental, inpatient model of the cocaine binge and abstinence cycle to examine the course and magnitude of sleep disturbances during cocaine use and abstinence.

METHODS

Five inpatient non-treatment seeking cocaine users completed 3 baseline days of drug abstinence followed by 3 days of medically monitored "binge" cocaine use, and then 15 days of drug abstinence. Physiological sleep was recorded with polysomnography and the Nightcap ambulatory monitor, while subjective sleep was assessed by questionnaire.

RESULTS

Across 3 days of binge cocaine use and 15 subsequent days of confirmed drug abstinence, mean sleep duration, efficiency and latency changed in the direction of poorer sleep quality. In contrast, subjective reports of sleep quality remained unchanged across the same period.

CONCLUSIONS

Physiological sleep quality deteriorated from days when cocaine was used across the first 2 weeks of confirmed drug abstinence. In contrast, subjective reports of sleep quality remained unchanged across the same period. We postulate that this dissociation between objective and subjective sleep quality results from a cocaine-use related disruption of the sleep homeostat. Worsening sleep quality during cocaine abstinence may contribute to the risk of relapse and its treatment may offer novel therapeutic strategies for cocaine dependence.

Psychological distress, physical illness, and risk of coronary heart disease

STUDY OBJECTIVE

The aims of this study are to confirm the association between psychological distress and coronary heart disease (CHD) using an epidemiological community study with hospital admissions data and to examine if any association is explained by existing illness.

DESIGN

Prospective cohort study modelling the association between psychological distress, measured using the 30 item general health questionnaire (GHQ), and hospital admissions data for CHD (ICD 410-414), using proportional hazards modelling adjusted for sociodemographic, CHD risk factors, and angina, bronchitis, diabetes, ischaemia, and stroke.

SETTING

Two suburbs of Glasgow, Renfrew and Paisley, in Scotland.

PARTICIPANTS

6575 men and women aged 45-64 years from Paisley.

MAIN RESULTS

Five year CHD risk in distressed men compared with non-distressed men was 1.78 (95% confidence intervals (CI), 1.15 to 2.75) in age adjusted analysis, 1.78 (95% CI, 1.14 to 2.79) with sociodemographic and CHD risk factor adjustment, and 1.61 (95% CI 1.02 to 2.55) with additional adjustment for existing illness. Psychological distress was unrelated to five year CHD risk in women. In further analysis, compared with healthy, non-distressed men, distressed physically ill men had a greater risk of CHD than non-distressed physically ill men, a relative risk of 4.01 (95% CI 2.42 to 6.66) compared with 2.12 (95% CI 1.35 to 3.32).

CONCLUSION

The association of psychological distress with an increased risk of five year CHD risk in men could be a function of baseline physical illness but an effect independent of physical illness cannot be ruled out. Its presence among physically ill men greatly increases CHD risk.

Childhood IQ and all-cause mortality before and after age 65: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies

OBJECTIVES

The objective was to investigate how childhood IQ related to all-cause mortality before and after age 65.

DESIGN

The Midspan prospective cohort studies, followed-up for mortality for 25 years, were linked to individuals' childhood IQ from the Scottish Mental Survey 1932.

METHODS

The Midspan studies collected data on risk factors for cardiorespiratory disease from a questionnaire and at a screening examination, and were conducted on adults in Scotland in the 1970s. An age 11 IQ from the Scottish Mental Survey 1932, a cognitive ability test conducted on 1921-born children attending schools in Scotland, was found for 938 Midspan participants. The relationship between childhood IQ and mortality risk, adjusting for adulthood socio-economic confounders, was analysed. The effect of adjustment for childhood IQ on the relationship between established risk factors (blood pressure, smoking, height and respiratory function) and mortality was also investigated.

RESULTS

For deaths occurring up to age 65, there was a 36% increased risk per standard deviation decrease (15 points) in childhood IQ which was reduced to 29% after adjusting for social class and deprivation category. There was no statistically significant relationship between childhood IQ and deaths occurring after the age of 65. Adjustment for childhood IQ attenuated the risk factor-mortality relationship in deaths occurring up to age 65, but had no effect in deaths occurring after age 65.

CONCLUSIONS

Childhood IQ was significantly related to deaths occurring up to age 65, but not to deaths occurring after age 65.

Gender effects following repeated administration of cocaine and alcohol in humans

RATIONALE

Use of cocaine, alcohol, and the two drugs simultaneously is common and the risk of morbidity and mortality associated with these drugs is widely reported. This double-blind, placebo-controlled, randomized study examined gender differences in response to administration of these drugs alone and in combination.

METHODS

Current users of cocaine and alcohol (n = 17) who met diagnostic criteria (DSM-IV) for cocaine dependence and alcohol abuse or dependence (not physiologically dependent on alcohol) and who were not seeking treatment for substance use disorders gave voluntary, written, informed consent to participate in three drug administration sessions:1) four doses of intranasal cocaine (1 mg/kg every 30 min) with oral alcohol (1 g/kg following the initial cocaine dose and a second drink at +60 min (120 mg/kg) calculated to maintain a plasma alcohol concentration of approximately 100 mg/dL; 2)four doses of cocaine and alcohol placebo; 3) cocaine placebo and alcohol. Pharmacokinetics were obtained by serial blood sampling, physiological measurements (heart rate and blood pressure) were obtained with automated equipment, and subjective effects were assessed using visual analog scales over 480 min.

RESULTS

Responses to cocaine, alcohol, and cocaine-alcohol were equivalent by gender for most measurements. Women had higher heart rates following alcohol administration (p = .02). Women consistently reported higher ratings for "Feel Good:' a measure of overall mental/physical well-being, for all study conditions, reaching statistical significance for cocaine (p = .05) and approaching significance for alcohol administration (p = .1).

CONCLUSION

Women showed equivalent responses to drug administration with the exception of perception of well-being, which was significantly increased for women. These findings may have implications for differential risk for acute and chronic toxicity in women.

Childhood IQ and cardiovascular disease in adulthood: prospective observational study linking the Scottish Mental Survey 1932 and the Midspan studies

This study investigated the influence of childhood IQ on the relationships between risk factors and cardiovascular disease (CVD), coronary heart disease (CHD) and stroke in adulthood. Participants were from the Midspan prospective cohort studies which were conducted on adults in Scotland in the 1970s. Data on risk factors were collected from a questionnaire and at a screening examination, and participants were followed up for 25 years for hospital admissions and mortality. 938 Midspan participants were successfully matched with their age 11 IQ from the Scottish Mental Survey 1932, in which 1921-born children attending schools in Scotland took a cognitive ability test. Childhood IQ was negatively correlated with diastolic and systolic blood pressure, and positively correlated with height and respiratory function in adulthood. For each of CVD, CHD and stroke, defined as either a hospital admission or death, there was an increased relative rate per standard deviation decrease (15 points) in childhood IQ of 1.11 (95% confidence interval 1.01-1.23), 1.16 (1.03-1.32) and 1.10 (0.88-1.36), respectively. With events divided into those first occurring before and those first occurring after the age of 65, the relationships between childhood IQ and CVD, CHD and stroke were only seen before age 65 and not after age 65. Blood pressure, height, respiratory function and smoking were associated with CVD events. Relationships were stronger in the early compared to the later period for smoking and FEV1, and stronger in the later compared to the earlier period for blood pressure. Adjustment for childhood IQ had small attenuating effects on the risk factor-CVD relationship before age 65 and no effects after age 65. Adjustment for risk factors attenuated the childhood IQ-CVD relationship by a small amount before age 65. Childhood IQ was associated with CVD risk factors and events and can be considered an important new risk factor.

Amantadine does not modulate reinforcing, subjective, or cardiovascular effects of cocaine in humans

Data from several clinical studies have suggested that amantadine, which has dopaminergic agonist and glutamatergic antagonist effects, may be useful for the treatment of cocaine dependence. The interaction between amantadine and smoked cocaine was examined in 10 cocaine smokers (7 men, 3 women), who participated in a 26-day inpatient study. Participants were maintained on amantadine (0 and 100 mg bid) for 5 days prior to laboratory testing, using a double-blind crossover design. Under each medication condition, participants smoked a sample dose of cocaine base (0, 12, 25, and 50 mg) once, and were subsequently given five choice opportunities, 14 min apart, to self-administer that dose of cocaine or receive a merchandise voucher ($5.00). Each cocaine dose was tested twice under each medication condition, and the order of medication condition and cocaine dose varied systematically. Cocaine produced stimulant-like reinforcing, subjective, and physiological effects. Amantadine maintenance did not modify the choice to self-administer smoked cocaine. These findings, taken together with the decidedly mixed literature, suggest that amantadine (100 mg bid) will not have a role in the treatment of cocaine dependence.

Gabapentin maintenance decreases smoked cocaine-related subjective effects, but not self-administration by humans

Data from research with laboratory animals indicate that cocaine self-administration can be reduced by lambda-aminobutyric acid (GABA) agonists. Yet, the effectiveness of GABA agonists to decrease human cocaine self-administration has not been investigated under controlled laboratory conditions. The purpose of this study was to assess the effects of gabapentin, a GABA agonist, on cocaine-related behaviors, including self-administration, in human research participants under controlled laboratory conditions. During this 48-day double-blind, crossover design study, the effects of gabapentin (0, 600, and 1200 mg/d) maintenance on response to cocaine (0, 12, 25, and 50 mg) were investigated in seven cocaine abusers. Active cocaine significantly increased choice to self-administer cocaine, subjective-effect ratings (e.g., "Good Drug Effect"), blood pressure and heart rate (HR). Gabapentin did not reduce cocaine choice or cardiovascular measures, but it did decrease some subjective effects of cocaine (e.g., "Good Drug Effect" and "Anxious"). These data suggest that the cocaine-gabapentin combination was well-tolerated, and because some cocaine-related subjective effects were reduced by maintenance on relatively low gabapentin doses, future studies should test higher gabapentin doses.

Marijuana withdrawal in humans: effects of oral THC or divalproex

Abstinence following daily marijuana use can produce a withdrawal syndrome characterized by negative mood (eg irritability, anxiety, misery), muscle pain, chills, and decreased food intake. Two placebo-controlled, within-subject studies investigated the effects of a cannabinoid agonist, delta-9-tetrahydrocannabinol (THC: Study 1), and a mood stabilizer, divalproex (Study 2), on symptoms of marijuana withdrawal. Participants (n=7/study), who were not seeking treatment for their marijuana use, reported smoking 6-10 marijuana cigarettes/day, 6-7 days/week. Study 1 was a 15-day in-patient, 5-day outpatient, 15-day in-patient design. During the in-patient phases, participants took oral THC capsules (0, 10 mg) five times/day, 1 h prior to smoking marijuana (0.00, 3.04% THC). Active and placebo marijuana were smoked on in-patient days 1-8, while only placebo marijuana was smoked on days 9-14, that is, marijuana abstinence. Placebo THC was administered each day, except during one of the abstinence phases (days 9-14), when active THC was given. Mood, psychomotor task performance, food intake, and sleep were measured. Oral THC administered during marijuana abstinence decreased ratings of 'anxious', 'miserable', 'trouble sleeping', 'chills', and marijuana craving, and reversed large decreases in food intake as compared to placebo, while producing no intoxication. Study 2 was a 58-day, outpatient/in-patient design. Participants were maintained on each divalproex dose (0, 1500 mg/day) for 29 days each. Each maintenance condition began with a 14-day outpatient phase for medication induction or clearance and continued with a 15-day in-patient phase. Divalproex decreased marijuana craving during abstinence, yet increased ratings of 'anxious', 'irritable', 'bad effect', and 'tired.' Divalproex worsened performance on psychomotor tasks, and increased food intake regardless of marijuana condition. Thus, oral THC decreased marijuana craving and withdrawal symptoms at a dose that was subjectively indistinguishable from placebo. Divalproex worsened mood and cognitive performance during marijuana abstinence. These data suggest that oral THC, but not divalproex, may be useful in the treatment of marijuana dependence.

Zolpidem-related effects on performance and mood during simulated night-shift work

The effects of zolpidem, a nonbenzodiazepine hypnotic, on psychomotor task performance, subjective effects, and food intake were examined during simulated shift work. Seven participants completed this 23-day, within-participant design, residential laboratory study. They received a single oral zolpidem dose (0, 5, or 10 mg) 1 hr before bedtime for 3 consecutive days under 2 shift conditions: day shift and night shift. When participants received placebo, next-day performance and subjective effects were disrupted, and food intake was decreased during the night shift. Zolpidem improved subjective reports of sleep quality and, to a lesser extent, next-day performance. Next-day mood, however, was worsened by zolpidem. Food intake was unaffected by zolpidem. These data indicate that shift changes produce performance impairments, mood alterations, and decreases in food intake, and that zolpidem attenuates some shift-change-related disruptions.