The main outcome measures were employment status and return to work after TBI. Methodological quality of most of the relevant 12 controlled and 68 uncontrolled studies included in the review was estimated as very low. There was weak evidence that age, educational level, pre- and post-injury occupational status, severity of TBI, functional status, level of depression and anxiety, gender and race may be predictive for the vocational outcome after TBI. CONCLUSIONS AND IMPLICATIONS FOR FURTHER RESEARCH: No strong evidence was found that vocational outcomes after TBI could be predicted or improved. There is a need for both experimental and observational well-conducted studies on this important subject. Researchers are strongly encouraged to use unified and standardized terms and scales in further studies. The authors suggest the International Classification of Functioning, Disability and Health (ICF) as the best tool available for this purpose.

The rates of human multiple maternities in the Nordic countries were studied from continuous series of data. In the Åland and Åboland archipelagos the parish records for births and baptisms since the 1650's were used. Various sources, some unpublished, in the archives of statistics were used for Sweden (since 1749) and Finland (since 1859) as a whole. Until recently, the rates of multizygotic multiple maternities in isolated island populations in the Åland and Åboland archipelagos have been some of the highest known among Whites (15-20‰). Highly significant temporal fluctuations in the twinning rates were noted. In Sweden, the twinning rate during the last part of 18th century was about twice as high as it was in 1966-70. The triplet and quadruplet rates were about three to four times as high as they are nowadays. There has been a secular decline in DZ twinning. This downward trend set in first in the isolated populations. In Sweden, it started in the 1930's, but in Finland, not until the 1960's. The steep downward trend in the twinning rates is shown to set in about one generation after the break-up of isolation. This can be interpreted as evidence that the changes in matrimonial migration patterns have affected the rates of DZ twinning.

We assess the effect of lumbar fusion (LF) in reducing disability among patients with chronic low back pain (CLBP) compared with conservative treatment and to weigh the clinical significance of this effect. We conducted a random-effect meta-analysis on the basis of a systematic review with research quality grading according to Grading of Recommendations Assessment, Development and Evaluation (GRADE). The studies included were retrieved from MEDLINE and Cochrane CENTRAL databases from 1990 till January 2013. Randomized or nonrandomized controlled studies were included if the study participants had a history of CLBP because of degenerative spinal diseases and had been treated with LF. A study was included if it compared LF with conservative treatment. The outcome measure was a change in the Oswestry Disability Index (ODI) score during a follow-up. The meta-analysis included data on 666 patients (402 cases) who participated in four randomized-controlled trials. The ODI score reduced in the LF and the control groups. The mean reduction in the ODI score in the follow-up of 1.5 years was -2.91 (95% confidence interval -6.66 to 0.84) in favor of LF. The difference between groups was statistically and clinically insignificant. Test for heterogeneity indicated that study imputation would favor LF but the imputed result would still be clinically insignificant with an estimated corrected reduction of ODI score of -5.51 (95% confidence interval -5.78 to -5.24). There is strong evidence that LF is not more effective than conservative treatment in reducing perceived disability because of CLBP among patients with degenerative spinal diseases. It is unlikely that further research on the subject would considerably affect this conclusion.

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