Smoking relapse prevention counseling during prenatal and early postnatal care.

Our objective was to examine the efficacy of the added effect of individualized smoking relapse prevention counseling on obstetricians' and nurse midwives' usual advice during prenatal care. One hundred and seventy-five pregnant women who were smoking early in their pregnancy, but had quit by first prenatal visit, were randomly assigned to receive the usual advice from their obstetrician or nurse midwife, or usual advice plus individual relapse prevention counseling. Smoking status was measured by self-report, by urinary cotinine/creatinine ratio at the 36-week visit, and by self-report at long-term postpartum follow-up. We found that a smaller percentage of women in the intervention group (8.8%) reported smoking at the thirty-sixth-week visit than those in the usual care group (16.9%), a nonsignificant difference. No significant difference in relapse rates during pregnancy was observed based on urinary cotinine/creatinine ratios, but these rates, 29.5% and 27.9% respectively, were substantially higher than those based on self-report. The average number of days abstinent reported by women in the intervention group was significantly longer than that in the usual care group, 199 days versus 166 days respectively (P < .01). Logistic regression analysis indicated that longest time abstaining before first visit, level of belief in smoking's harm to the fetus, and motivation to smoke were independently related to the probability of relapsing to smoking by the 36-week visit. Long-term relapse rates were not significantly different: intervention group, 50.9%, usual care group, 50.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of long-term non-fatiguing resistance exercise in subjects with post-polio syndrome.

Measures of torque were used to evaluate changes in muscle strength and endurance in 17 patients with post-polio syndrome who did prescribed resistance exercise for up to 2 years. Exercise compliance averaged 75%, with 16 subjects increasing the weight lifted in training. Maximum torque was significantly increased in the exercised muscle compared to the control muscle; no difference was seen in muscle endurance. Individuals with post-polio syndrome can increase muscle strength by doing non-fatiguing resistance exercise, but they should undergo quantitative testing of muscle strength a minimum of every 3 months to guard against overwork weakness.

The magnitude and variability of design effects for community intervention studies.

Despite inadequate replication of treatment and comparison groups in community intervention studies, suitable estimates of variance can be obtained by multiplying the simple random sampling variance by a design effect, which can be estimated from other sources. To study the stability of these estimates, the authors performed a detailed investigation of the magnitude and sources of variability of design effects for age-adjusted mortality rates for selected causes of death separately for each of 44 US states. The authors made use of age-sex-race-county-specific data from the Compressed Mortality File generated by the National Center for Health Statistics. Design effects were calculated as the ratio of a cluster (county) sampling variance to the simple random sampling variance. The effects of sex, state, and year on the magnitude of the design effects were investigated by analysis of variance. Design effects were 2.33, 1.66, 1.24, 1.08, and 1.06 for ischemic heart disease, stroke, and cancers of the lung, breast, and colon, respectively. The largest source of variability was state; 35-70% of this variability could be attributed to the states' differing population sizes. The effect of sex was minimal. These results are relevant to the planning and analysis of community intervention studies.

Estimation of the design effect in community intervention studies.

This paper considers the estimation of the variance of a mortality rate in community intervention studies with little or no replication of intervention regimens. Our approach in estimation of this cluster sampling variance is to determine the variance for simple random sampling and multiply it by a design effect which we calculate with use of information obtained from other sources. When the county is the unit of randomization and the outcome is mortality, we calculate the design effect as the ratio of the age adjusted mortality rates for single stage cluster sampling relative to simple random sampling; we use information from all counties in a state in the calculations. We apply this approach empirically for breast cancer mortality. We found that these design effects were dependent on length of time for accumulation of deaths (1.1 for one year up to 3.5 for eight years) and were quite consistent for the three states and nine years considered in the investigation. We present a model that accounts for the time dependence of the design effect and we show it provides a good representation of the observed relationship.

The translocation of inhaled silicon dioxide: an empirically derived compartmental model.

The movement of inhaled silicon dioxide particles was studied by measuring the amounts in alveolar fluid and cells, lung tissue, and lymphoid tissue during the 6 months following short-term aerosol exposure of Fischer 344 rats. A variety of first-order compartmental models were fit to data from nine exposure experiments to identify the most feasible biologic pathways for the transfer of material among these sites and out of the body. A multivariate least-squares approach was used to simultaneously fit the data from several compartments. The results indicate that transfer between alveolar cells and lung tissue occurs in both directions, suggesting that silica can reenter the alveolar space from the lung tissue. This feature has not been included in previously published models. The results also indicate that transfer from lung tissue to the mediastinal lymph nodes and thymus is indirect; there are one or more unidentified extrapulmonary compartments that receive silica from the lung. Rates of transfer among compartments were dependent on mineral type (quartz or cristobalite), heat treatment, and exposure dose. There was no evidence for direct clearance from the alveolar space via the tracheobronchial tract.

Individualized smoking cessation counseling during prenatal and early postnatal care.

OBJECTIVE: We examined the efficacy of individualized smoking cessation counseling added to obstetricians' and nurse-midwives' advice. STUDY DESIGN: In a mixed private and publicly supported prenatal clinic 600 pregnant women who smoked were randomly assigned to receive the usual advice from their obstetrician or nurse-midwife or the usual advice plus individualized smoking cessation counseling. Smoking status was measured by self-report and urinary cotinine/creatinine ratios at 36 weeks and by self-report during long-term postpartum follow-up. RESULTS: Quitting rates during pregnancy were not increased by adding individualized smoking cessation counseling to usual care. At the long-term follow-up, reported quitting rates were significantly greater among intervention group women cared for in the publicly supported clinic than among those receiving the usual care, 14.5% versus 2.5%, p < 0.01. CONCLUSION: Although adding individual smoking cessation counseling did not increase quitting rates during pregnancy, it should be considered for women in public maternity clinics because of its potential long-term effectiveness.